@article{sulis_jiang_yang_marques_matthews_miller_lan_cofre-vega_liu_sun_et al._2023, title={Multiplex CRISPR editing of wood for sustainable fiber production}, volume={381}, ISSN={["1095-9203"]}, url={http://europepmc.org/abstract/med/37440632}, DOI={10.1126/science.add4514}, abstractNote={The domestication of forest trees for a more sustainable fiber bioeconomy has long been hindered by the complexity and plasticity of lignin, a biopolymer in wood that is recalcitrant to chemical and enzymatic degradation. Here, we show that multiplex CRISPR editing enables precise woody feedstock design for combinatorial improvement of lignin composition and wood properties. By assessing every possible combination of 69,123 multigenic editing strategies for 21 lignin biosynthesis genes, we deduced seven different genome editing strategies targeting the concurrent alteration of up to six genes and produced 174 edited poplar variants. CRISPR editing increased the wood carbohydrate-to-lignin ratio up to 228% that of wild type, leading to more-efficient fiber pulping. The edited wood alleviates a major fiber-production bottleneck regardless of changes in tree growth rate and could bring unprecedented operational efficiencies, bioeconomic opportunities, and environmental benefits.}, number={6654}, journal={SCIENCE}, author={Sulis, Daniel B. and Jiang, Xiao and Yang, Chenmin and Marques, Barbara M. and Matthews, Megan L. and Miller, Zachary and Lan, Kai and Cofre-Vega, Carlos and Liu, Baoguang and Sun, Runkun and et al.}, year={2023}, month={Jul}, pages={216-+} }
 @article{jiang_wan_kollman_jiang_wu_jameel_chang_2023, title={Role of extractable lignin in enzymatic hydrolysis of hydrothermally pretreated hardwood}, volume={193}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2022.116150}, abstractNote={The role of solvent extractable lignin in enzymatic hydrolysis of hydrothermally pretreated sweetgum was investigated. Lignin extraction with acetone, methanol or acetone/methanol removed 27–33% of lignin in hydrothermally pretreated sweetgum pulp, resulting in total sugar yield reduction. Comprehensive characterization indicated that the extractable lignin is highly degraded with low molecular weight, high phenolic hydroxyls, and low native lignin interunit linkages and exhibited neither stimulation nor inhibition effects on enzymatic hydrolysis of filter paper, Avicel, and bleached eucalyptus kraft pulp. The extractable lignin was mainly deposited on the surface of the fibers and pores, which removal caused significant morphological change and collapse of the mesopores and macropores. Thus, the reduction in enzymatic digestion efficiency was more likely caused by the pore collapse in fiber and decreased accessible area, rather than the stimulative action of the extractable lignin.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Jiang, Xiao and Wan, Shanqi and Kollman, Matthew and Jiang, Huicong and Wu, Shufang and Jameel, Hasan and Chang, Hou-min}, year={2023}, month={Mar} }
 @article{jiang_sun_kollman_chang_jameel_2023, title={Structure and property variations of mixed hardwood kraft lignins}, ISSN={["1532-2319"]}, DOI={10.1080/02773813.2023.2262974}, abstractNote={Abstract Kraft lignin as an emerging renewable feedstock can be used to produce fuels, chemicals, and materials. Hardwood kraft lignin bears intrinsic variation due to wood species and the isolation process. The structure and property variation of hardwood kraft lignin could introduce new challenges and opportunities for its application. To better understand such variation, seven kraft lignin samples, originated from southern mixed hardwood (North America), northern mixed hardwood (North America), and Asian mixed hardwood, were isolated from commercial kraft pulping black liquor using both LignoBoost and LignoForce processes. Modern analytical techniques were used to elucidate the characteristics of mixed hardwood kraft lignins, including chemical composition, molecular weight, functional groups, and thermal properties. All lignin samples had a lignin content over 90% (92% to 96%) with one exception, which was northern mixed hardwood kraft lignin with 86% of lignin content and 6% polysaccharides. The elemental and methoxy analyses revealed the expected variation of hardwood kraft lignins with the methoxy content ranging from 0.85 to 1.20 per C9 unit. The weight average molecular weight exhibited a higher variation (from 4800 to 1895 Da) with a descending order of southern mixed hardwood kraft lignins, northern mixed hardwood lignins, and Asian mixed hardwood lignins. The aliphatic hydroxy groups ranged from 14 to 25 per 100 C9 units, and phenolic hydroxy groups ranged from 65 to 112 per 100 C9 units. The catecholic group content ranged from 12 to 34 per 100 C9 units, which is higher than softwood kraft lignin. The lignins isolated from the rapid displacement heating (RDH) pulping process were more condensed than from the regular kraft pulping process. 2D HSQC and quantitative 13C NMR revealed the drastic structure change upon kraft pulp with the low abundance of native lignin linkages and formation of new interunit linkages, such as stilbene, enol ethers, and 1-1’/5’. The S/G ratio was calculated using 2D HSQC spectra correcting for signal shift caused by the catecholic groups.}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Jiang, Xiao and Sun, Runkun and Kollman, Matthew and Chang, Hou-min and Jameel, Hasan}, year={2023}, month={Sep} }
 @article{kollman_jiang_sun_zhang_li_chang_jameel_2023, title={Towards jet fuel from technical lignins: Feedstock-catalyst-product interactions revealed during catalytic hydrogenolysis}, volume={451}, ISSN={["1873-3212"]}, DOI={10.1016/j.cej.2022.138464}, abstractNote={One-pot conversion of technical lignins to jet fuel is limited by recondensation of unstable intermediates. A two-stage process that first generates stabilized fragments by reductive depolymerization, then upgrades oligomers to hydrocarbons may increase yield. Insights into factors affecting initial depolymerization of industrially relevant lignins were revealed, whereas many studies have focused on upgrading bio-oil or model compounds. Feedstocks, catalysts, and process conditions were varied to identify effects on product composition. Hydrogen and temperature synergistically suppressed coking during pine kraft depolymerization to increase monomer production. Ruthenium was more effective than cobalt at limiting solid residue and improving liquid product yield by promoting hydrogenation and hydrogenolysis. Besides ruthenium, a strong acid-base catalyst effectively deconstructed hardwood biorefinery lignin, targeting alkyl-aryl ether bonds. Ruthenium and zinc converted hardwood kraft lignin to oligomers most suitable for upgrading to jet fuel-range hydrocarbons based on yield (79 % on dry lignin), weight-average molecular weight (1290 g/mol), and chemical structure.}, journal={CHEMICAL ENGINEERING JOURNAL}, author={Kollman, Matthew S. and Jiang, Xiao and Sun, Runkun and Zhang, Xia and Li, Wenzhi and Chang, Hou-min and Jameel, Hasan}, year={2023}, month={Jan} }
 @article{vera_vivas_urdaneta_franco_sun_forfora_frazier_gongora_saloni_fenn_et al._2023, title={Transforming non-wood feedstocks into dissolving pulp via organosolv pulping: An alternative strategy to boost the share of natural fibers in the textile industry.}, volume={429}, ISSN={["1879-1786"]}, url={https://doi.org/10.1016/j.jclepro.2023.139394}, DOI={10.1016/j.jclepro.2023.139394}, abstractNote={This work evaluates wheat straw, switchgrass, and hemp hurd as potential alternatives for producing dissolving pulp using sulfur dioxide (SO2)-ethanol-water (SEW) pulping. The SEW process is described in detail for wheat straw, and the best pulping conditions for this feedstock were 130 °C, 4 h, and 10% SO2 concentration, comprised in a sulfur-ethanol-water ratio of 10-45-45. This resulted in a viscose-grade pulp with 93% α-cellulose, 2.0% hemicelluloses, <0.1% lignin, 0.2% ash content, and a viscosity of 4.7 cP. The best pulping conditions for wheat straw were applied to switchgrass and hemp hurd. Wheat straw and switchgrass had similar pulp quality, while hemp hurd pulp had a higher hemicellulose content and lower viscosity. This work suggests that non-wood feedstocks such as wheat straw and switchgrass can be promising alternatives for dissolving pulp production, which can help reduce the pressure on the textile industry to increase the use of natural fibers and mitigate the environmental impact of non-biodegradable synthetic fibers.}, journal={JOURNAL OF CLEANER PRODUCTION}, author={Vera, Ramon E. and Vivas, Keren A. and Urdaneta, Fernando and Franco, Jorge and Sun, Runkun and Forfora, Naycari and Frazier, Ryen and Gongora, Stephanie and Saloni, Daniel and Fenn, Larissa and et al.}, year={2023}, month={Dec} }
 @article{jardim_hart_lucia_jameel_chang_2022, title={The Effect of the Kraft Pulping Process, Wood Species, and pH on Lignin Recovery from Black Liquor}, volume={10}, ISSN={["2079-6439"]}, url={https://www.mdpi.com/2079-6439/10/2/16}, DOI={10.3390/fib10020016}, abstractNote={Lignin has shown a great potential to produce fuels, value-added chemicals, and functional materials due to its high-energy density and intrinsic aromatic-based structure. Yet, the lignin precipitation of different biomasses needs investigation because most of the work has been performed on softwood and much less is known about hardwoods. In fact, the lignin from these two wooden biomasses vary in composition and pulping performance, which can reflect on lignin precipitation. Therefore, the present study investigated the precipitation and composition of 40 distinct kraft lignins obtained from pine, acacia, sweetgum, and eucalyptus black liquors. Two lignin fractions were precipitated at different pHs, according to known industrial lignin separation practices (pH = 9.5 and 2.5) from black liquors taken at different levels of pulping. Overall, lignin recovery increased with increasing lignin concentration in the black liquor, i.e., higher amounts of lignin were obtained at higher levels of delignification. In addition, pine lignins showed superior yields than the hardwoods and were around five times purer. Among the hardwoods, lignin recovery increased with the S–G ratio of the native lignin, and eucalyptus showed the best performance by achieving the highest yields and purities. Finally, the present work compared the lignin recovery yield and the purity of softwood and different hardwood lignins in a systematic way, which will increase awareness of this underutilized green material and could potentially increase the interest in establishing new lignin plants across the globe.}, number={2}, journal={FIBERS}, author={Jardim, Juliana M. and Hart, Peter W. and Lucia, Lucian A. and Jameel, Hasan and Chang, Hou-min}, year={2022}, month={Feb} }
 @article{kollman_jiang_thompson_mante_dayton_chang_jameel_2021, title={Improved understanding of technical lignin functionalization through comprehensive structural characterization of fractionated pine kraft lignins modified by the Mannich reaction}, ISSN={["1463-9270"]}, DOI={10.1039/d1gc01842f}, abstractNote={Detailed investigation of structural changes following kraft lignin amination. Identification of factors that affected reaction route and yield, and evaluation of different characterization methods will aid kraft lignin applied research efforts.}, journal={GREEN CHEMISTRY}, author={Kollman, Matthew and Jiang, Xiao and Thompson, Samuel J. and Mante, Ofei and Dayton, David C. and Chang, Hou-min and Jameel, Hasan}, year={2021}, month={Aug} }
 @article{jardim_hart_lucia_jameel_chang_2020, title={A Quantitative Comparison of the Precipitation Behavior of Lignin from Sweetgum and Pine Kraft Black Liquors}, volume={15}, ISSN={["1930-2126"]}, DOI={10.15376/biores.15.3.5464-5480}, abstractNote={Lignin is a by-product of the pulp and paper industry that can be precipitated by acidification from black liquor as a potential feedstock for valuable green materials. Precipitation and quantification of lignin from softwood black liquors have been documented and commercialized with well-established methods; however, applying those methods to the precipitation of lignin from hardwood black liquors has produced low lignin yields. A need to understand the main differences between hardwood and softwood lignin precipitation prompted the current investigation. Multiple black liquor samples from sweetgum and pine pulping were obtained at different times of standard kraft cooks. Two lignin fractions were precipitated from each of these black liquors, one at pH 9.5 and one at pH 2.5. Detailed lignin and carbohydrate material balances were performed around each of the sample sets, starting with the wood and ending with precipitated lignin fractions. For all conditions tested, the amount and purity of pine lignin precipitated were superior to sweetgum lignin. The maximum recovery for sweetgum lignin was 69.7%, while for pine lignin, it was 90.9%.}, number={3}, journal={BIORESOURCES}, author={Jardim, Juliana M. and Hart, Peter W. and Lucia, Lucian and Jameel, Hasan and Chang, Houmin}, year={2020}, month={Aug}, pages={5464–5480} }
 @misc{chang_jiang_2020, title={Biphenyl structure and its impact on the macromolecular structure of lignin: A critical review}, volume={40}, ISSN={["1532-2319"]}, DOI={10.1080/02773813.2019.1697297}, abstractNote={Abstract Biphenyl linkage is the second most abundant linkage in softwood lignin; the β-O-4′ linkage being the most abundant linkage. That about 20–28% of monolignols are linked by biphenyl linkage has been demonstrated by UV spectroscopy, permanganate oxidation, 13C NMR, and thioacidolysis followed by 31P NMR. Most, if not all, of the biphenyl structures in softwood lignin are etherified, indicating that biphenyl structures are formed while monolignols are being transported to the lignifying zone during lignin biosynthesis. Along with 4-O-5′ (∼3/100 C9 units), β-6′/α-6′ (∼3/100 C9) and noncyclic α-O-4′ structures (4/100 C9), biphenyl structures are the major branching points of lignin structure. Thus, at least one out of every three C9 units in softwood lignin are branching units. This fact indicates that softwood lignin is most likely a network polymer. Many alkyl-aryl ether bonds are cleaved during ball milling for the isolation of Milled Wood Lignin (MWL), but the number of branching points remains the same. Therefore, softwood milled wood lignin, with a number average DP of 20, exists most likely as at least a highly branched polymer and unlikely as a linear polymer. Harwood lignin has less biphenyl structures (∼9%), but has more 4-O-5′ (∼7%), noncyclic α-O-4′ (6%) and similar β-6′/α-6′ (∼2%) linkages as compared with softwood lignin. Thus, only one out of every four C9 units is a branching point, indicating that hardwood lignin is most likely a highly branched polymer. Hardwood MWL is most likely a branched polymer, but one cannot rule out the chance of finding a few linear oligomers in MWL. One potential branching point is not considered in the above discussion. The lignin-carbohydrate complexes are also branching points in lignin. The number of LCC linkages in native lignin cannot be determined precisely.}, number={2}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Chang, Hou-Min and Jiang, Xiao}, year={2020}, month={Mar}, pages={81–90} }
 @article{geng_venditti_pawlak_chang_pal_ford_2020, title={Carboxymethylation of hemicellulose isolated from poplar (Populus grandidentata) and its potential in water-soluble oxygen barrier films}, volume={27}, ISSN={0969-0239 1572-882X}, url={http://dx.doi.org/10.1007/s10570-020-02993-2}, DOI={10.1007/s10570-020-02993-2}, number={6}, journal={Cellulose}, publisher={Springer Science and Business Media LLC}, author={Geng, Wenhui and Venditti, Richard A. and Pawlak, Joel J. and Chang, Hou-ming and Pal, Lokendra and Ford, Ericka}, year={2020}, month={Jan}, pages={3359–3377} }
 @article{an_li_xue_li_xia_liu_chen_jameel_chang_2020, title={Effect of removing hemicellulose and lignin synchronously under mild conditions on enzymatic hydrolysis of corn stover}, volume={204}, ISSN={0378-3820}, url={http://dx.doi.org/10.1016/j.fuproc.2020.106407}, DOI={10.1016/j.fuproc.2020.106407}, abstractNote={P-toluene sulfonic acid (PTSA) was utilized to pretreat corn stover. Changes in morphology and structure of untreated and pretreated samples were analyzed by ESEM, TEM, BET, XRD and SXT. The characterization results demonstrated that PTSA pretreatment could markedly improve cellulase accessibility to cellulose because of the removal of lignin and hemicellulose simultaneously. The maximum glucose yield (67.2%) with an enzyme loading of 5FPU•g−1 substrate was achieved after the sample was the pretreated at 80 °C for 10 min with 71.0 wt% PTSA. P-toluene sulfonic acid pretreatment was a valid method to improve the enzymatic hydrolysis performance of cellulose in corn stover at low reaction temperature with a short reaction time.}, journal={Fuel Processing Technology}, publisher={Elsevier BV}, author={An, Shengxin and Li, Wenzhi and Xue, Fengyang and Li, Xu and Xia, Ying and Liu, Qiyu and Chen, Liang and Jameel, Hasan and Chang, Hou-min}, year={2020}, month={Jul}, pages={106407} }
 @article{wu_chen_jameel_chang_phillips_jin_2020, title={Effects of Lignin Contents and Delignification Methods on Enzymatic Saccharification of Loblolly Pine}, volume={59}, ISSN={["0888-5885"]}, DOI={10.1021/acs.iecr.0c00645}, abstractNote={Softwood pulp is more recalcitrant toward enzymatic hydrolysis than hardwood or nonwood pulps. Pulps of various kappa numbers were prepared from loblolly pine chips by kraft cooking, which was foll...}, number={18}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Wu, Shufang and Chen, Hui and Jameel, Hasan and Chang, Hou-min and Phillips, Richard and Jin, Yongcan}, year={2020}, month={May}, pages={8532–8537} }
 @article{dou_jiang_li_zhu_liu_lu_zheng_chang_jameel_2020, title={Highly efficient conversion of Kraft lignin into liquid fuels with a Co-Zn-beta zeolite catalyst}, volume={268}, ISSN={["1873-3883"]}, DOI={10.1016/j.apcatb.2019.118429}, abstractNote={Kraft lignin depolymerization to liquid fuels with high yields is crucial to the comprehensive achievement of sustainable and economic feasibility. Herein, we prepared a bimetallic Co-Zn/Off-Al H-beta catalyst through a two-step post synthesis method composed of dealumination and metal incorporation. The bifunctional Co-Zn/Off-Al H-beta catalyst efficiently converted Kraft lignin to liquid fuels, which was attributable to the synergistic effect of Co hydrogen binding sites and Zn Lewis acid sites on H-beta support. Catalytic hydrogenation with Co:Zn = 1:3/Off-Al H-beta catalyst at 320 °C for 24 h gave the highest yield of petroleum ether soluble product (81%, mainly monomers and dimers). Under these conditions, the liquefied lignin gave a higher heating value of 33.3 MJ/kg, which is a significant increase from 26.0 MJ/kg of Kraft lignin. The catalyst stability test showed excellent recyclability. This work provides a paradigm of improving lignin depolymerization efficiency via the combined use of Lewis acid and hydrogenation catalyst.}, journal={APPLIED CATALYSIS B-ENVIRONMENTAL}, author={Dou, Xiaomeng and Jiang, Xiao and Li, Wenzhi and Zhu, Chaofeng and Liu, Qingchuan and Lu, Qiang and Zheng, Xusheng and Chang, Hou-min and Jameel, Hasan}, year={2020}, month={Jul} }
 @article{jiang_assis_kollman_sun_jameel_chang_gonzalez_2020, title={Lignin fractionation from laboratory to commercialization: chemistry, scalability and techno-economic analysis}, volume={22}, ISSN={["1463-9270"]}, url={https://doi.org/10.1039/D0GC02960B}, DOI={10.1039/d0gc02960b}, abstractNote={A detailed techno-economic analysis on industrial scale lignin fractionation using green solvents.}, number={21}, journal={GREEN CHEMISTRY}, publisher={Royal Society of Chemistry (RSC)}, author={Jiang, Xiao and Assis, Camilla and Kollman, Matthew and Sun, Runkun and Jameel, Hasan and Chang, Hou-min and Gonzalez, Ronalds}, year={2020}, month={Nov}, pages={7448–7459} }
 @article{geng_venditti_pawlak_de assis_gonzalez_phillips_chang_2020, title={Techno-economic analysis of hemicellulose extraction from different types of lignocellulosic feedstocks and strategies for cost optimization}, volume={14}, ISBN={1932-1031}, ISSN={1932-104X 1932-1031}, url={http://dx.doi.org/10.1002/bbb.2054}, DOI={10.1002/bbb.2054}, abstractNote={Abstract}, number={2}, journal={BIOFUELS BIOPRODUCTS & BIOREFINING-BIOFPR}, publisher={Wiley}, author={Geng, Wenhui and Venditti, Richard A. and Pawlak, Joel J. and De Assis, Tiago and Gonzalez, Ronalds W. and Phillips, Richard B. and Chang, Hou-min}, year={2020}, month={Mar}, pages={225–241} }
 @article{jiang_narron_han_park_chang_jameel_2020, title={Tracing Sweetgum Lignin's Molecular Properties through Biorefinery Processing}, volume={13}, ISSN={["1864-564X"]}, DOI={10.1002/cssc.202001125}, abstractNote={Abstract}, number={17}, journal={CHEMSUSCHEM}, author={Jiang, Xiao and Narron, Robert H. and Han, Qiang and Park, Sunkyu and Chang, Hou-min and Jameel, Hasan}, year={2020}, month={Sep}, pages={4613–4623} }
 @article{ribeiro_vaz junior_jameel_chang_narron_jiang_colodette_2019, title={Chemical Study of Kraft Lignin during Alkaline Delignification of E. urophylla x E. grandis Hybrid in Low and High Residual Effective Alkali}, volume={7}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.8b06635}, abstractNote={Chips from E. urophylla x E. grandis hybrid were subjected to kraft cooking using two different approaches: low and high residual effective alkali. The lignin remaining in the pulps were analyzed for hydroxyl and carboxyl functional groups. For both pulping cases, the kappa number varied between 14 and 26. Significant yield gains were observed when kraft cooking was terminated with low residual effective alkali (L-REA) in contrast to those with high residual effective alkali (H-REA) at a given kappa number. The L-REA pulps also tended to contain higher lignin and lower HexA contents than the H-REA pulps at a given kappa number. Cellulolytic enzyme lignin (CEL) was isolated from the studied pulp’s residual lignins, and their hydroxyl functional group distributions were quantified using a method involving ³¹P NMR. Analysis of residual lignins isolated from L-REA and H-REA cooking indicated that L-REA had high contents of phenolic hydroxyl groups and carboxylic acid groups in relation to the H-REA pulps. This work demonstrates the varied lignin chemistry one can expect when residual effective alkali levels are varied during kraft pulping and how this parameter can influence downstream unit operations and overall process performance.}, number={12}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Ribeiro, Robisnea Adriana and Vaz Junior, Silvio and Jameel, Hasan and Chang, Hou-Min and Narron, Robert and Jiang, Xiao and Colodette, Jorge Luiz}, year={2019}, month={Jun}, pages={10274–10282} }
 @article{jardim_du_hart_lucia_jameel_chang_gracz_2019, title={Fundamental molecular characterization and comparison of the 0, D-0, and E stage effluents from hardwood pulp bleaching}, volume={18}, ISSN={["0734-1415"]}, DOI={10.32964/TJ18.6.341}, abstractNote={The present study characterized effluents from the O, D0, and E stages using nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques to better understand the chemical nature of the dissolved organics formed from the bleaching of a high-yield hardwood kraft pulp. Understanding the structures and molecular weight distribution of these organics is the first step in developing methods to mitigate these contaminates in the discharged effluents. The results indicated that the molecular weight distribution (MWD) of the dissolved organics from oxygen delignification effluent is broader than those from D0 and E stage effluents. In addition, the O stage filtrate contained considerable amounts of lignin and xylan fragments, which showed its efficiency in removing such materials. The effluent from the D0 stage contained a lower amount of high molecular weight fragments and a higher amount of low molecular weight fragments versus the O-stage filtrate. Aromatic structures were nearly absent in the D0 stage filtrate, but the degraded organic material, presumably from oxidized lignin, contained olefinic (C=C) and carbonyl (C=O) functional groups. Furthermore, higher molecular weight fragments were detected in the E-stage effluent, presumably due to the extensive solubilization and removal of the oxidized lignin generated from the D0 pulp.}, number={6}, journal={TAPPI JOURNAL}, author={Jardim, Juliana M. and Du, Xueyu and Hart, Peter W. and Lucia, Lucian and Jameel, Hasan and Chang, Hou-Min and Gracz, Hanna}, year={2019}, month={Jun}, pages={341–351} }
 @article{huang_sun_chang_yong_jameel_phillips_2019, title={Production of Dissolving Grade Pulp from Tobacco Stalk Through SO2-ethanol-water Fractionation, Alkaline Extraction, and Bleaching Processes}, volume={14}, ISSN={["1930-2126"]}, DOI={10.15376/biores.14.3.5544-5558}, abstractNote={The objective of this study was to evaluate the possibility of producing dissolving grade pulp from tobacco stalk through combining SO2-ethanol-water (SEW) fractionation, alkaline extraction, and bleaching with oxygen (O), chlorine dioxide (D), alkaline extraction with hydrogen peroxide (Ep), and hydrogen peroxide (P) (OD0(Ep)D1P). The results showed that the optimum SEW cooking condition to remove the original xylan and lignin in tobacco stalk to an acceptable level was 6% SO2 charge (by weight) at 135 °C for 180 min. A bleachable pulp (Kappa number of 21.5) was produced from the SEW-treated tobacco stalk via a subsequent 1% NaOH extraction. After the OD0(Ep)D1P sequence bleaching, the bleached pulp showed a high brightness (88.1% ISO) and a high α-cellulose content (94.9%). The viscosity (15.8 cP) and the residual xylan content (4.4%) of the pulp were within acceptable levels for dissolving pulp production. Thus, tobacco stalk was shown to be a viable raw material for dissolving pulp production following a SEW treatment, alkaline extraction, and a conventional bleaching sequence.}, number={3}, journal={BIORESOURCES}, author={Huang, Caoxing and Sun, Runkun and Chang, Hou-min and Yong, Qiang and Jameel, Hasan and Phillips, Richard}, year={2019}, month={Aug}, pages={5544–5558} }
 @article{zhang_jiang_lin_zhao_chang_jameel_2019, title={Reactivity improvement by phenolation of wheat straw lignin isolated from a biorefinery process}, volume={43}, ISSN={["1369-9261"]}, DOI={10.1039/c8nj05016c}, abstractNote={This work describes an effective phenolation process to improve wheat straw biorefinery lignin reactivity.}, number={5}, journal={NEW JOURNAL OF CHEMISTRY}, author={Zhang, Fangda and Jiang, Xiao and Lin, Jian and Zhao, Guangjie and Chang, Hou-min and Jameel, Hasan}, year={2019}, month={Feb}, pages={2238–2246} }
 @article{geng_narron_jiang_pawlak_chang_park_jameel_venditti_2019, title={The influence of lignin content and structure on hemicellulose alkaline extraction for non-wood and hardwood lignocellulosic biomass}, volume={26}, ISSN={0969-0239 1572-882X}, url={http://dx.doi.org/10.1007/s10570-019-02261-y}, DOI={10.1007/s10570-019-02261-y}, number={5}, journal={Cellulose}, publisher={Springer Science and Business Media LLC}, author={Geng, Wenhui and Narron, Robert and Jiang, Xiao and Pawlak, Joel J. and Chang, Hou-min and Park, Sunkyu and Jameel, Hasan and Venditti, Richard A.}, year={2019}, month={Jan}, pages={3219–3230} }
 @article{he_han_jameel_chang_phillips_wang_2018, title={Comparison of One-Stage Batch and Fed-Batch Enzymatic Hydrolysis of Pretreated Hardwood for the Production of Biosugar}, volume={184}, ISSN={["1559-0291"]}, DOI={10.1007/s12010-017-2633-y}, abstractNote={Fed-batch method has shown a great promise in debottlenecking the high-solid enzymatic hydrolysis for the commercialization of cellulosic biosugar conversion for biofuel/biochemical production. To further improve enzymatic hydrolysis efficiency at high solid loading, fed-batch methods of green liquor-pretreated hardwood were performed to evaluate their effects on sugar recovery by comparing with one-stage batch method in this study. Among all the explored conditions, the fed-batch at 15% consistency gave higher sugar recovery on green liquor-pretreated hardwood compared to that of one-stage batch. By using general linear model analysis, the percentage of enzymatic sugar recovery in fed-batch consistency method (increasing consistency from the initial 10.7 to 15% at intervals of 24 and 48 h) was higher than that of batch hydrolysis at higher density of 15% consistency. Under that best fed-batch condition, the total sugar recovery of pretreated hardwood in enzymatic hydrolysate reached approximately 48.41% at Cellic® enzyme loading of 5 filter-paper unit (FPU)/g and 58.83% at Cellic® enzyme loading of 10 FPU/g with a hydrolysis time of 96 h.}, number={4}, journal={APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY}, author={He, Liang and Han, Qiang and Jameel, Hasan and Chang, Hou-min and Phillips, Richard and Wang, Ziyu}, year={2018}, month={Apr}, pages={1441–1452} }
 @article{wang_matthews_williams_shi_yang_tunlaya-anukit_chen_li_liu_lin_et al._2018, title={Improving wood properties for wood utilization through multi-omics integration in lignin biosynthesis}, volume={9}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/s41467-018-03863-z}, DOI={10.1038/s41467-018-03863-z}, abstractNote={Abstract}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Wang, Jack P. and Matthews, Megan L. and Williams, Cranos M. and Shi, Rui and Yang, Chenmin and Tunlaya-Anukit, Sermsawat and Chen, Hsi-Chuan and Li, Quanzi and Liu, Jie and Lin, Chien-Yuan and et al.}, year={2018}, month={Apr}, pages={1579} }
 @misc{londono-zuluaga_du_chang_jameel_gonzalez_2018, title={Lignin Modifications and Perspectives towards Applications of Phenolic Foams: A Review}, volume={13}, ISSN={["1930-2126"]}, DOI={10.15376/biores.13.4.Londono-Zuluaga}, abstractNote={Lignin is a complex natural polymer and by-product of the pulp and paper industry. Currently, the increasing interest in bio-based products has motivated the search for alternative renewable feedstocks that can sustainably replace synthetic polymers. Because of the phenolic functionalities of lignin, this natural polymer has attracted interest for application in biomaterials. Among various products, polymeric foams stand out as a potential product in which lignin incorporation has resulted in improved mechanical and thermal properties. This paper reviews the state of lignin foam development, with emphasis placed on phenol-lignin types.}, number={4}, journal={BIORESOURCES}, author={Londono-Zuluaga, Carolina and Du, Jing and Chang, Hou-Min and Jameel, Hasan and Gonzalez, Ronalds}, year={2018}, pages={9158–9179} }
 @article{jiang_liu_du_hu_chang_jameel_2018, title={Phenolation to Improve Lignin Reactivity toward Thermosets Application}, volume={6}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.8b00369}, abstractNote={Phenolation can be used to improve the reactivity and decrease the molecular weight of lignin, thereby making it more useful for various applications. We report an effective phenolation process with only a catalytic amount of sulfuric acid and using phenol as solvent. The optimum phenolation conditions for pine kraft lignin and sweetgum biorefinery lignin were determined to be lignin/phenol (L/P, wt/wt) of 3/5, 5% acid charge at 90 °C for 2 h and L/P of 2/5, 5% acid charge at 110 °C for 2 h, respectively. Phenolation resulted in introducing 30 wt % of phenol onto pine kraft lignin and 60 wt % of phenol onto sweetgum biorefinery lignin and significantly decreasing in the molecular weight of lignin. Phenol was incorporated onto both the side chains and aromatic nuclei of lignin. All lignin substructures of β-O-4′, β-5′/α-O-4′, β–β′, α-carbonyl, etc. were reacted, resulting in a significant decrease in aliphatic hydroxyl groups and increase in the phenolic hydroxyl groups. The comprehensive characterization ...}, number={4}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Jiang, Xiao and Liu, Jie and Du, Xueyu and Hu, Zhoujian and Chang, Hou-min and Jameel, Hasan}, year={2018}, month={Apr}, pages={5504–5512} }
 @article{li_dou_zhu_wang_chang_jameel_li_2018, title={Production of liquefied fuel from depolymerization of kraft lignin over a novel modified nickel/H-beta catalyst}, volume={269}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2018.08.125}, abstractNote={In this study, a novel modified nickel/H-beta (Ni/DeAl-beta) catalyst, which has active acidic sites and hydrogen binding sites, was prepared and used to produce liquefied fuel from lignin. The bifunctional Ni/DeAl-beta catalyst efficiently converted kraft lignin into liquefied fuel due to the synergistic effect of aluminum Lewis acid sites and nickel hydrogen binding sites. At a nickel content of 0.6 mmol/gzeolite, the Ni/DeAl-beta catalyst gave a high liquid product yield of 88.6% at 300 °C for 36 h. Most of the liquid product was dissolved in petroleum ether (73% of 88.6%), which was mainly composed of monomeric and dimeric degradation products. Under these conditions, the higher heating values (HHV) increased from 24.9 MJ/kg for kraft lignin to 32.0 MJ/kg for the liquid product. These results demonstrated the bifunctional Ni/DeAl-beta catalyst could be an efficient catalyst for lignin to liquefied fuel conversion.}, journal={BIORESOURCE TECHNOLOGY}, author={Li, Wenzhi and Dou, Xiaomeng and Zhu, Chaofeng and Wang, Jindong and Chang, Hou-min and Jameel, Hasan and Li, Xiaosen}, year={2018}, month={Dec}, pages={346–354} }
 @article{wang_li_wang_chang_jameel_zhang_li_jin_2017, title={A ternary composite oxides S2O82-/ZrO2-TiO2SiO2 as an efficient solid super acid catalyst for depolymerization of lignin}, volume={7}, ISSN={["2046-2069"]}, DOI={10.1039/c7ra09489b}, abstractNote={The solid, super, acid catalyst S2O82−/ZrO2–TiO2–SiO2, which has both a strong Brønsted acid and Lewis acid, was prepared and applied in lignin depolymerization.}, number={79}, journal={RSC ADVANCES}, author={Wang, Huizhen and Li, Wenzhi and Wang, Jindong and Chang, Hou-min and Jameel, Hasan and Zhang, Qi and Li, Song and Jin, Lele}, year={2017}, pages={50027–50034} }
 @article{an_li_liu_li_ma_ma_chang_2017, title={A two-stage pretreatment using acidic dioxane followed by dilute hydrochloric acid on sugar production from corn stover}, volume={7}, ISSN={["2046-2069"]}, DOI={10.1039/c7ra05280d}, abstractNote={A two-stage pretreatment method was developed to improve sugar recovery in this study.}, number={52}, journal={RSC ADVANCES}, author={An, Shengxin and Li, Wenzhi and Liu, Qiyu and Li, Minghao and Ma, Qiaozhi and Ma, Longlong and Chang, Hou-min}, year={2017}, pages={32452–32460} }
 @article{huang_he_chang_jameel_yong_2017, title={Coproduction of Ethanol and Lignosulfonate From Moso Bamboo Residues by Fermentation and Sulfomethylation}, volume={8}, ISSN={["1877-265X"]}, DOI={10.1007/s12649-016-9629-7}, number={3}, journal={WASTE AND BIOMASS VALORIZATION}, author={Huang, Caoxing and He, Juan and Chang, Hou-min and Jameel, Hasan and Yong, Qiang}, year={2017}, month={Apr}, pages={965–974} }
 @article{li_zhu_lu_liu_guan_chang_jameel_ma_2017, title={Enhanced furfural production from raw corn stover employing a novel heterogeneous acid catalyst}, volume={245}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2017.08.077}, abstractNote={With the aim to enhance the direct conversion of raw corn stover into furfural, a promising approach was proposed employing a novel heterogeneous strong acid catalyst (SC-CaCt-700) in different solvents. The novel catalyst was characterized by elemental analysis, N2 adsorption-desorption, FT-IR, XPS, TEM and SEM. The developed catalytic system demonstrated superior efficacy for furfural production from raw corn stover. The effects of reaction temperature, residence time, catalyst loading, substrate concentration and solvent were investigated and optimized. 93% furfural yield was obtained from 150 mg corn stover at 200 °C in 100 min using 45 mg catalyst in γ-valerolactone (GVL). In comparison, 51.5% furfural yield was achieved in aqueous media under the same conditions (200 °C, 5 h, and 45 mg catalyst), which is of great industrial interest. Furfural was obtained from both hemicelluloses and cellulose in corn stover, which demonstrated a promising routine to make the full use of biomass.}, journal={BIORESOURCE TECHNOLOGY}, author={Li, Wenzhi and Zhu, Yuanshuai and Lu, Yijuan and Liu, Qiyu and Guan, Shennan and Chang, Hou-min and Jameel, Hasan and Ma, Longlong}, year={2017}, month={Dec}, pages={258–265} }
 @article{xiang_sen_min_savithri_lu_jameel_chiang_chang_2017, title={Field-Grown Transgenic Hybrid Poplar with Modified Lignin Biosynthesis to Improve Enzymatic Saccharification Efficiency}, volume={5}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.6b02740}, abstractNote={Hybrid poplars (Populus nigra L. × Populus maximowiczii A.) were genetically modified through antisense insertion of the 4-coumarate:coenzyme A ligase (4CL) gene. Compositional changes in response to this genetic change were measured in the field after 2 and 3 years of growth. The stem samples were treated with either green liquor or dilute acid pretreatments, representing alkaline and acid pretreatments. The enzymatic saccharification of the untreated and pretreated transgenic poplars were evaluated. After transgenic species were transplanted into the environment, they showed reduced recalcitrance to chemicals (i.e., pretreatments) and enzymes despite their lignin content and S/V ratio being comparable to those of the wild types. Compared to the field-grown poplars, the sugar yield increased up to 103% for untreated transgenic samples and increased 22% for acid- and green liquor-pretreated transgenic samples. This shows that field-grown transgenic hybrid poplars with modified lignin biosynthesis have imp...}, number={3}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Xiang, Zhouyang and Sen, Suman Kumar and Min, Douyong and Savithri, Dhanalekshmi and Lu, Fachuang and Jameel, Hasan and Chiang, Vincent and Chang, Hou-min}, year={2017}, month={Mar}, pages={2407–2414} }
 @article{jiang_savithri_du_pawar_jameel_chang_zhou_2017, title={Fractionation and Characterization of Kraft Lignin by Sequential Precipitation with Various Organic Solvents}, volume={5}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.6b02174}, abstractNote={The value-added utilizations of technical lignin are restricted by its heterogeneous features, such as high polydispersity, complex functional group distribution, ununiformed reactivity, etc. Fractionation of lignin into more homogeneous parts represents a promising approach to overcome this challenge. In the present study, softwood kraft lignin was fractionated into four different portions (F1, F2, F3, and F4) by first dissolving it in a methanol–acetone mixture followed by sequential precipitation with various organic solvents (ethyl acetate, 1:1 ethyl acetate/petroleum ether, petroleum ether) of decreasing solubility parameters. The yields of various fractions F1, F2, F3, and F4 were 48%, 39%, 10%, and 3%, respectively. The results from gel permeation chromatography indicated that the molecular weights of each fraction decreased from F1 to F4. The lowest molecular weight fraction F4 contained mainly monomeric and dimeric aromatic structures such as guaiacol and vanillin formed from lignin degradation. ...}, number={1}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Jiang, Xiao and Savithri, Dhanalekshmi and Du, Xueyu and Pawar, Siddhesh and Jameel, Hasan and Chang, Hou-Min and Zhou, Xiaofan}, year={2017}, month={Jan}, pages={835–842} }
 @article{li_li_lu_jameel_chang_ma_2017, title={High conversion of glucose to 5-hydroxymethylfurfural using hydrochloric acid as a catalyst and sodium chloride as a promoter in a water/gamma-valerolactone system}, volume={7}, ISSN={["2046-2069"]}, DOI={10.1039/c7ra00701a}, abstractNote={HCl as a catalyst and NaCl as a promoter result in impressive selectivity and HMF yield in a water/γ-valerolactone system.}, number={24}, journal={RSC ADVANCES}, author={Li, Minghao and Li, Wenzhi and Lu, Yijuan and Jameel, Hasan and Chang, Hou-min and Ma, Longlong}, year={2017}, pages={14330–14336} }
 @article{narron_han_park_chang_jameel_2017, title={Lignocentric analysis of a carbohydrate-producing lignocellulosic biorefinery process}, volume={241}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2017.05.207}, abstractNote={A biologically-based lignocellulosic biorefinery process for obtaining carbohydrates from raw biomass was investigated across six diverse biomasses (three hardwoods & three nonwoods) for the purpose of decoding lignin's influence on sugar production. Acknowledging that lignin could positively alter the economics of an entire process if valorized appropriately, we sought to correlate the chemical properties of lignin within the process to the traditional metrics associated with carbohydrate production-cellulolytic digestibility and total sugar recovery. Based on raw carbohydrate, enzymatic recovery ranged from 40 to 64% w/w and total recovery ranged from 70 to 87% w/w. Using nitrobenzene oxidation to quantify non-condensed lignin structures, it was found that raw hardwoods bearing increasing non-condensed S/V ratios (2.5-5.1) render increasing total carbohydrate recovery from hardwood biomasses. This finding indicates that the chemical structure of hardwood lignin influences the investigated biorefinery process' ability to generate carbohydrates from a given raw hardwood feedstock.}, journal={BIORESOURCE TECHNOLOGY}, author={Narron, Robert H. and Han, Qiang and Park, Sunkyu and Chang, Hou-min and Jameel, Hasan}, year={2017}, month={Oct}, pages={857–867} }
 @article{wang_li_wang_ma_li_chang_jameel_2017, title={Liquefaction of kraft lignin by hydrocracking with simultaneous use of a novel dual acid-base catalyst and a hydrogenation catalyst}, volume={243}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2017.06.024}, abstractNote={In this study, a novel catalyst, S2O82−-KNO3/TiO2, which has active acidic and basic sites, was prepared and used in lignin hydrocracking with a co-catalyst, Ru/C. Ru/C is an efficient hydrogenation catalyst and S2O82−-KNO3/TiO2 is a dual catalyst, which could efficiently degrade lignin. This catalytic hydrogenation system can reduce solid products to less than 1%, while giving a high liquid product yield of 93%. Catalytic hydrocracking of kraft lignin at 320 °C for 6 h gave 93% liquid product with 0.5% solid product. Most of this liquid product was soluble in petroleum ether (60% of 93%), which is a clear liquid and comprises mainly of monomeric and dimeric degradation products. These results demonstrated that the combination of the two catalysts is an efficient catalyst for liquefaction of lignin, with little char formation (∼1%). This concept has the potential to produce valuable chemicals and fuels from lignin under moderate conditions.}, journal={BIORESOURCE TECHNOLOGY}, author={Wang, Jindong and Li, Wenzhi and Wang, Huizhen and Ma, Qiaozhi and Li, Song and Chang, Hou-min and Jameel, Hasan}, year={2017}, month={Nov}, pages={100–106} }
 @article{zhu_li_lu_zhang_jameel_chang_ma_2017, title={Production of furfural from xylose and corn stover catalyzed by a novel porous carbon solid acid in gamma-valerolactone}, volume={7}, ISSN={["2046-2069"]}, DOI={10.1039/c7ra03995f}, abstractNote={An efficient catalytic system using S-RFC as catalyst was developed to produce furfural from xylose and corn stover in GVL.}, number={48}, journal={RSC ADVANCES}, author={Zhu, Yuanshuai and Li, Wenzhi and Lu, Yijuan and Zhang, Tingwei and Jameel, Hasan and Chang, Hou-min and Ma, Longlong}, year={2017}, pages={29916–29924} }
 @article{narron_chang_jameel_park_2017, title={Soluble Lignin Recovered from Biorefinery Pretreatment Hydrolyzate Characterized by Lignin-Carbohydrate Complexes}, volume={5}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.7b02716}, abstractNote={The lignin rendered soluble by lignocellulosic biorefinery pretreatment remains insufficiently understood along the lines of molecular properties and chemical composition. To procure a representative soluble lignin preparation, an aromatic-selective adsorptive resin was utilized. Approximately 90% of soluble lignin could be recovered from autohydrolysis pretreatment hydrolyzate (autohydrolyzate) produced from a hardwood and a nonwood biomass. Adsorbate compositional characterization revealed a befuddling magnitude of carbohydrate in selectively isolated lignin adsorbates. Quantitative structural analysis of the lignin by NMR suggested lignin–carbohydrate complexes (LCCs) as the cause behind the pronounced carbohydrate contents. Analyzed spectra revealed both hardwood and nonwood soluble lignin features of ∼10 total LCC per 100 aromatic rings, with each lignin bearing unique LCC profiles. In addition, native structures remained in large quantities. The improved understanding of hydrolyzate-soluble lignin g...}, number={11}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Narron, Robert H. and Chang, Hou-min and Jameel, Hasan and Park, Sunkyu}, year={2017}, month={Nov}, pages={10763–10771} }
 @article{li_li_liu_jameel_chang_an_ma_2016, title={A Two-Step Conversion of Corn Stover into Furfural and Levulinic Acid in a Water/Gamma-Valerolactone System}, volume={11}, ISSN={["1930-2126"]}, DOI={10.15376/biores.11.4.8239-8256}, abstractNote={A two-step hydrolysis method was evaluated as a potential means of obtaining high yields of furfural and levulinic acid from corn stover using sulfuric acid as catalyst in a water/gamma-valerolactone (GVL) system. The corn stover underwent a high-temperature hydrolysis process to produce levulinic acid, followed by a low-temperature hydrolysis process to produce furfural. A series of experiments were conducted to explore the relationship between the different reaction parameters and the final yields of furfural and levulinic acid. Scanning electron microscopy (SEM) pictures together with X-ray diffraction (XRD) analysis were used to further elaborate on the hydrolysis results. Molar yields of about 70.65% furfural and 57.7% levulinic acid were obtained by applying this method with a low temperature of 140 °C and a high temperature of 190 °C, together with 0.2 M of sulfuric acid used as the catalyst. These results indicated that this was an effective way to obtain satisfactory yields of furfural and levulinic acid from corn stover.}, number={4}, journal={BIORESOURCES}, author={Li, Minghao and Li, Wenzhi and Liu, Qiyu and Jameel, Hasan and Chang, Hou-min and An, Shengxin and Ma, Longlong}, year={2016}, month={Nov}, pages={8239–8256} }
 @article{li_liu_ma_zhang_ma_jameel_chang_2016, title={A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover}, volume={219}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2016.08.025}, abstractNote={A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading.}, journal={BIORESOURCE TECHNOLOGY}, author={Li, Wenzhi and Liu, Qiyu and Ma, Qiaozhi and Zhang, Tingwei and Ma, Longlong and Jameel, Hasan and Chang, Hou-min}, year={2016}, month={Nov}, pages={753–756} }
 @misc{narron_kim_chang_jameel_park_2016, title={Biomass pretreatments capable of enabling lignin valorization in a biorefinery process}, volume={38}, ISSN={["1879-0429"]}, DOI={10.1016/j.copbio.2015.12.018}, abstractNote={Recent techno-economic studies of proposed lignocellulosic biorefineries have concluded that creating value from lignin will assist realization of biomass utilization into valuable fuels, chemicals, and materials due to co-valorization and the new revenues beyond carbohydrates. The pretreatment step within a biorefinery process is essential for recovering carbohydrates, but different techniques and intensities have a variety of effects on lignin. Acidic and alkaline pretreatments have been shown to produce diverse lignins based on delignification chemistry. The valorization potential of pretreated lignin is affected by its chemical structure, which is known to degrade, including inter-lignin condensation under high-severity pretreatment. Co-valorization of lignin and carbohydrates will require dampening of pretreatment intensities to avoid such effects, in spite of tradeoffs in carbohydrate production.}, journal={CURRENT OPINION IN BIOTECHNOLOGY}, author={Narron, Robert H. and Kim, Hoyong and Chang, Hou-min and Jameel, Hasan and Park, Sunkyu}, year={2016}, month={Apr}, pages={39–46} }
 @article{li_xu_zhang_li_jameel_chang_ma_2016, title={Catalytic Conversion of Biomass-derived Carbohydrates into 5-Hydroxymethylfurfural using a Strong Solid Acid Catalyst in Aqueous gamma-Valerolactone}, volume={11}, ISSN={["1930-2126"]}, DOI={10.15376/biores.11.3.5839-5853}, abstractNote={Selective conversion of biomass-derived carbohydrates into 5-hydroxy-methylfurfural (HMF) is of great significance for biomass conversion. In this study, a novel solid Bronsted acid was prepared simply by the copolymerization of paraformaldehyde and p-toluenesulfonic acid and then used to catalyze the conversion of various carbohydrates into HMF in γ-valerolactone-water (GVL/H2O) reaction medium for the first time. The catalyst exhibited strong acidity, good water resistance, and high thermal stability. The present work focuses on the effects of various reaction parameters, including reaction temperature, time, water concentration, solvent, fructose level, and catalyst loading, on fructose dehydration. The catalyst exhibited excellent catalytic performance for HMF production from fructose in GVL and furnished a high HMF yield of 78.1% at 130 °C in 30 min. The recycling experiments suggested that the solid acid catalyst could be recycled at least seven times without a noticeable decrease in the catalytic activity. In addition, an attempt to study the one-step conversion of sucrose, glucose, and cellulose into HMF and furfural was performed using the same catalytic system.}, number={3}, journal={BIORESOURCES}, author={Li, Wenzhi and Xu, Zhiping and Zhang, Tingwei and Li, Guojun and Jameel, Hasan and Chang, Hou-min and Ma, Longlong}, year={2016}, month={Aug}, pages={5839–5853} }
 @article{zhang_li_xu_liu_ma_jameel_chang_ma_2016, title={Catalytic conversion of xylose and corn stalk into furfural over carbon solid acid catalyst in gamma-valerolactone}, volume={209}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2016.02.108}, abstractNote={A novel carbon solid acid catalyst was synthesized by the sulfonation of carbonaceous material which was prepared by carbonization of sucrose using 4-BDS as a sulfonating agent. TEM, N2 adsorption–desorption, elemental analysis, XPS and FT-IR were used to characterize the catalyst. Then, the catalyst was applied for the conversion of xylose and corn stalk into furfural in GVL. The influence of the reaction time, temperature and dosage of catalyst on xylose dehydration were also investigated. The Brønsted acid catalyst exhibited high activity in the dehydration of xylose, with a high furfural yield of 78.5% at 170 °C in 30 min. What’s more, a 60.6% furfural yield from corn stalk was achieved in 100 min at 200 °C. The recyclability of the sulfonated carbon catalyst was perfect, and it could be reused for 5 times without the loss of furfural yields.}, journal={BIORESOURCE TECHNOLOGY}, author={Zhang, Tingwei and Li, Wenzhi and Xu, Zhiping and Liu, Qiyu and Ma, Qiaozhi and Jameel, Hasan and Chang, Hou-min and Ma, Longlong}, year={2016}, month={Jun}, pages={108–114} }
 @article{du_li_xu_wu_jameel_chang_ma_2016, title={Characterization Of C-60/Bi2TiO4F2 as a Potential Visible Spectrum Photocatalyst for The Depolymerization of Lignin}, volume={36}, ISSN={["1532-2319"]}, DOI={10.1080/02773813.2016.1173063}, abstractNote={Effects of a photocatalyst, C60-modified Bi2TiO4F2, on pine kraft lignin under visible light irradiation were investigated, along with those of Bi2TiO4F2 and C60/TiO2 as references. The influences of pH, C60 mass fraction, and the initial lignin concentration on lignin conversion and yields of mono-phenolic products were investigated. Seven products were determined by GC/MS, including phenol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol, vanillin, acetovanillone, and homovanillic acid. The yields of products and lignin conversion were higher by C60/Bi2TiO4F2 than Bi2TiO4F2 and C60/TiO2. C60/Bi2TiO4F2 and C60/TiO2 were more stable than Bi2TiO4F2 upon repetitive recycling of catalyst. The effectiveness of C60/Bi2TiO4F2 declines 25%, whereas that of Bi2TiO4F2 declines 56.4% after being recycled five times. FTIR and HRTEM indicated that the deactivation of photocatalysts might be caused by lignin adsorbed on the surface of photocatalysts and the change in the crystal structure.}, number={5}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Du, Zhijie and Li, Wenzhi and Xu, Zhiping and Wu, Hao and Jameel, Hasan and Chang, Hou-Min and Ma, Long-Long}, year={2016}, pages={365–376} }
 @article{pawar_venditti_jameel_chang_ayoub_2016, title={Engineering physical and chemical properties of softwood kraft lignin by fatty acid substitution}, volume={89}, ISSN={0926-6690}, url={http://dx.doi.org/10.1016/j.indcrop.2016.04.070}, DOI={10.1016/j.indcrop.2016.04.070}, abstractNote={A process to attach fatty acids to lignin is reported which alters its thermal behavior. By attaching saturated C18 fatty acids to OH groups, stable lignin stearates (LS) of controllable degrees of substitution (DS) were synthesized. Interesting physical properties were observed, wherein LS was observed to melt and flow at temperatures as low as 50 °C. Melting was possible due to the crystallization of stearate chains when LS was purified by precipitation. A NMR method was established for quantification of the degree of substitution. At very high %DS values (close to 100%), the melting phenomenon was reversible, but at low %DS, melting occurred only during the 1st heating ramp during thermal cycling. The ability of LS to plasticize polystyrene (PS) is reported wherein integral blend films containing up to 25% by weight of LS were formed. The Tg of the blended films could be lowered by 22 °C using LS relative to PS. Lignin stearates have the potential to serve as interesting compounds for their ability to plasticize not only PS but other thermoplastic materials as well.}, journal={Industrial Crops and Products}, publisher={Elsevier BV}, author={Pawar, Siddhesh N. and Venditti, Richard A. and Jameel, Hasan and Chang, Hou-Min and Ayoub, Ali}, year={2016}, month={Oct}, pages={128–134} }
 @article{huang_jeuck_du_yong_chang_jameel_phillips_2016, title={Novel process for the coproduction of xylo-oligosaccharides, fermentable sugars, and lignosulfonates from hardwood}, volume={219}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2016.08.051}, abstractNote={Many biorefineries have not been commercialized due to poor economic returns from final products. In this work, a novel process has been developed to coproduce valuable sugars, xylo-oligosaccharides, and lignosulfonates from hardwood. The modified process includes a mild autohydrolysis pretreatment, which enables for the recovery of the xylo-oligosaccharides in auto-hydrolysate. Following enzymatic hydrolysis, the residue is sulfomethylated to produce lignosulfonates. Recycling the sulfomethylation residues increased both the glucan recovery and lignosulfonate production. The glucose recovery was increased from 81.7% to 87.9%. Steady state simulation using 100 g of hardwood produced 46.7 g sugars, 5.9 g xylo-oligosaccharides, and 25.7 g lignosulfonates, which were significantly higher than that produced from the no-recycling process with 39.1 g sugars, 5.9 g xylo-oligosaccharides, and 15.0 g lignosulfonates. The results indicate that this novel biorefinery process can improve the production of fermentable sugars and lignosulfonate from hardwood as compared to a conventional biorefinery process.}, journal={BIORESOURCE TECHNOLOGY}, author={Huang, Caoxing and Jeuck, Ben and Du, Jing and Yong, Qiang and Chang, Hou-min and Jameel, Hasan and Phillips, Richard}, year={2016}, month={Nov}, pages={600–607} }
 @article{liu_li_ma_an_li_jameel_chang_2016, title={Pretreatment of corn stover for sugar production using a two-stage dilute acid followed by wet-milling pretreatment process}, volume={211}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2016.03.131}, abstractNote={A two-stage process was evaluated to increase sugar recovery. Firstly, corn stover was treated with dilute hydrochloric acid to recover the xylose, and then the residue was subjected to a wet-milling pretreatment. Dilute hydrochloric acid showed a high xylose recovery during the first stage. The optimal condition was 120 °C and 40 min for 0.7 wt% dilute hydrochloric acid pretreatment followed by wet-milling pretreatment for 15 min. The xylose and glucose yield were 81.0% and 64.0%, respectively, with a cellulase dosage at 3 FPU/g of substrate. This two-stage process was effective on account of the removal of hemicelluloses in the first stage and the delamination of cell wall in the second stage, increasing the possibility of adsorption of cellulose to enzymes, and resulting in a high sugar recovery with a very low enzyme loading.}, journal={BIORESOURCE TECHNOLOGY}, author={Liu, Qiyu and Li, Wenzhi and Ma, Qiaozhi and An, Shengxin and Li, Minghao and Jameel, Hasan and Chang, Hou-min}, year={2016}, month={Jul}, pages={435–442} }
 @article{hu_du_liu_chang_jameel_2016, title={Structural Characterization of Pine Kraft Lignin: BioChoice Lignin vs Indulin AT}, volume={36}, ISSN={["1532-2319"]}, DOI={10.1080/02773813.2016.1214732}, abstractNote={BioChoice lignin (BCL) is a newly commercialized pine kraft lignin from Plymouth Mill of Domtar, which is precipitated from black liquor of bleachable-grade pulp. Indulin AT is a pine kraft lignin commercialized by Meadwestvaco for the past 60 years, which is precipitated from black liquor of linerboard-grade pulp. Thus, the two technical lignins are produced under quite different conditions in terms of alkali charge and pulping time/temperature. While the chemical structure of Indulin AT is well documented, that of BCL is totally unknown. In this study, chemical structures of BCL and Indulin AT are characterized using modern analytical techniques and compared with those of pine milled wood lignin (MWL) in order to elucidate the structural changes that occur during kraft pulping and the structural differences, if any, between BCL and Indulin AT. Both BCL and Indulin AT are structurally very different from the native lignin (MWL) in wood, indicating drastic structural modification during the kraft pulping process. Surprisingly, BCL and Indulin AT are structurally very similar, in spite of the fact that they are produced under different process conditions. However, there are subtle structural differences between BCL and Indulin AT. BCL has higher phenolic hydroxyl, catechol, enol ether, and stilbene contents, but lower methoxyl and β-O-4 contents. These differences are explained by the different pulping conditions under which the two technical lignins are produced.}, number={6}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Hu, Zhoujian and Du, Xueyu and Liu, Jie and Chang, Hou-min and Jameel, Hasan}, year={2016}, pages={432–446} }
 @article{balakshin_capanema_santos_chang_jameel_2016, title={Structural analysis of hardwood native lignins by quantitative C-13 NMR spectroscopy}, volume={70}, ISSN={["1437-434X"]}, DOI={10.1515/hf-2014-0328}, abstractNote={Abstract}, number={2}, journal={HOLZFORSCHUNG}, author={Balakshin, Mikhail Yu and Capanema, Ewellyn A. and Santos, Ricardo B. and Chang, Hou-min and Jameel, Hasan}, year={2016}, month={Feb}, pages={95–108} }
 @article{han_jin_jameel_chang_phillips_park_2015, title={Autohydrolysis Pretreatment of Waste Wheat Straw for Cellulosic Ethanol Production in a Co-located Straw Pulp Mill}, volume={175}, ISSN={["1559-0291"]}, DOI={10.1007/s12010-014-1349-5}, abstractNote={Waste wheat straw (WWS) is the waste product from feedstock preparation process in a straw pulp mill. It has a significant annual production rate and no commercial value has been explored on this material. In this study, waste wheat straw was pretreated using an autohydrolysis process followed by mechanical refining, and the pretreated materials were further enzymatically hydrolyzed to evaluate the total sugar recovery for bioethanol production. Results show that autohydrolysis at 170 °C for 40 min followed by 6000 revolution PFI refining provided the best result in this study, where a total sugar recovery (total sugars in autohydrolysis filtrate and enzymatic hydrolyzate over total carbohydrates on raw WWS) of 70 % at 4 filter paper unit per oven dry gram (FPU/OD g) substrate enzyme charge could be obtained. The economic evaluation of this biorefinery process indicates that cellulosic ethanol production from autohydrolysis of WWS is a very profitable business, with 28.4 % of internal rate of return can be achieved based on current ethanol wholesale price in China.}, number={2}, journal={APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY}, author={Han, Qiang and Jin, Yanbin and Jameel, Hasan and Chang, Hou-min and Phillips, Richard and Park, Sunkyu}, year={2015}, month={Jan}, pages={1193–1210} }
 @article{xu_li_du_wu_jameel_chang_ma_2015, title={Conversion of corn stalk into furfural using a novel heterogeneous strong acid catalyst in gamma-valerolactone}, volume={198}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2015.09.104}, abstractNote={A novel solid acid catalyst was prepared by the copolymerization of p-toluenesulfonic acid and paraformaldehyde and then characterized by FT-IR, TG/DTG, HRTEM and N2-BET. Furfural was successfully produced by the dehydration of xylose and xylan using the novel catalyst in γ-valerolactone. This investigation focused on effects of various reaction conditions including solvent, acid catalyst, reaction temperature, residence time, water concentration, xylose loading and catalyst dosage on the dehydration of xylose to furfural. It was found that the solid catalyst displayed extremely high activity for furfural production. 80.4% furfural yield with 98.8% xylose conversion was achieved at 170°C for 10 min. The catalyst could be recycled at least five times without significant loss of activity. Furthermore, 83.5% furfural yield and 19.5% HMF yield were obtained from raw corn stalk under more severe conditions (190°C for 100 min).}, journal={BIORESOURCE TECHNOLOGY}, author={Xu, Zhiping and Li, Wenzhi and Du, Zhijie and Wu, Hao and Jameel, Hasan and Chang, Hou-min and Ma, Longlong}, year={2015}, month={Dec}, pages={764–771} }
 @article{capanema_balakshin_katahira_chang_jameel_2015, title={HOW WELL DO MWL AND CEL PREPARATIONS REPRESENT THE WHOLE HARDWOOD LIGNIN?}, volume={35}, ISSN={["1532-2319"]}, DOI={10.1080/02773813.2014.892993}, abstractNote={Hardwood lignin preparations were isolated using classical milled wood lignin (MWL) and cellulolytic enzyme lignin (CEL) protocols. Furthermore, we managed to produce a lignin preparation of a very high yield, above 90%, with high purity and minimal structural degradation. This was achieved by dissolution and regeneration of milled wood prior to enzymatic hydrolysis, along with the use of 80% dioxane for lignin extraction. This preparation (RCEL-80) yield was about 4.5 and 2.5 times higher than the yields of the traditional MWL and CEL preparations, correspondingly, at the same milling time. The preparations obtained were comprehensively analyzed with state-of-the-art quantitative NMR techniques and wet chemistry methods. CELs were representative preparations for hardwood lignins as the S/G ratios in the CELs were equivalent to those in lignin in situ. Degradation of the main lignin subunits was very low. Importantly, the structures of CELs were independent of the preparation yield and were very similar to the structure of the high-yield lignin, RCEL-80. In contrast, the structures of MWLs were noticeably dependent on the preparation yield, especially when the yield was below 15–20% of total wood lignin. In particular, the S/G ratio increased with increasing MWL yield, but was still lower than the S/G ratios of the whole lignins in situ, even at high MWL yields. The amounts of β-O-4 lignin units in MWL were lower than those in the corresponding CEL preparations. It has been concluded that CEL preparations were representative of the whole wood lignin whereas MWLs represent a fraction with a lower S/G ratio.}, number={1}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Capanema, Ewellyn and Balakshin, Mikhail and Katahira, Rui and Chang, Hou-min and Jameel, Hasan}, year={2015}, pages={17–26} }
 @misc{li_zhang_du_ma_jameel_chang_2015, title={Photocatalytic degradation of lignin model compounds and kraft pine lignin by CdS/TiO2 under visible light irradiation}, volume={10}, DOI={10.15376/biores.10.1.1245-1259}, abstractNote={Cadium sulfide/titanium dioxide (CdS/TiO2) catalyst was prepared by two different methods: microemulsion-mediated solvothermal hydrolyzation (CdS/TiO2 (SH)) and in-situ sulfurization under supercritical conditions (CdS/TiO2 (SS)). The photocatalysts were characterized by nitrogen adsorption-desorption, X-ray diffraction, X-ray photoelectron spectra, UV-Vis absorption spectra, and PL spectra. Photodegradation reactions of three monomeric and one dimeric lignin model compounds, and kraft pine lignin (Indulin AT) were carried out at room temperature in a weak alkaline aqueous system by visible light irradiation with air bubbling. Quantitative results showed that these lignin model compounds and kraft lignin were effectively degraded. While both phenolic and non-phenolic lignin units are reactive, the phenolic units appeared to react faster and preferentially reacted.}, number={1}, journal={BioResources}, author={Li, W. Z. and Zhang, M. J. and Du, Z. J. and Ma, Q. Z. and Jameel, H. and Chang, H. M.}, year={2015}, pages={1245–1259} }
 @article{ribas batalha_han_jameel_chang_colodette_borges gomes_2015, title={Production of fermentable sugars from sugarcane bagasse by enzymatic hydrolysis after autohydrolysis and mechanical refining}, volume={180}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2014.12.060}, abstractNote={The autohydrolysis process has been considered a simple, low-cost and environmental friendly technology for generation of sugars from biomass. In order to improve accessibility of enzymes during enzymatic hydrolysis as well as to allow the recovery of hemicellulose in the filtrate, the sugarcane bagasse was pretreated using autohydrolysis followed by a mechanical refining process. The autohydrolysis was carried out in three different conditions. Autohydrolysis at 190 °C for 10 min provided the highest overall sugar (19.2/100 g raw bagasse) in prehydrolyzate. The enzymatic hydrolysis step was performed for all the post-treated solids with and without refining at enzyme loadings of 5 and 10 FPU/g for 96 h. A total of 84.4% of sugar can be recovered from sugarcane bagasse at 180 °C for 20 min with 5 FPU/g enzyme charge. The economic analysis for the proposed method showed that the bioethanol production can have a financial return larger than 12%.}, journal={BIORESOURCE TECHNOLOGY}, author={Ribas Batalha, Larisse Aparecida and Han, Qiang and Jameel, Hasan and Chang, Hou-min and Colodette, Jorge Luiz and Borges Gomes, Fernando Jose}, year={2015}, month={Mar}, pages={97–105} }
 @article{xiang_sen_roy_min_savithri_jameel_chiang_chang_2015, title={Wood characteristics and enzymatic saccharification efficiency of field-grown transgenic black cottonwood with altered lignin content and structure}, volume={22}, ISSN={["1572-882X"]}, DOI={10.1007/s10570-014-0541-7}, number={1}, journal={CELLULOSE}, author={Xiang, Zhouyang and Sen, Suman Kumar and Roy, Aparna and Min, Douyong and Savithri, Dhanalekshmi and Jameel, Hasan and Chiang, Vincent and Chang, Hou-min}, year={2015}, month={Feb}, pages={683–693} }
 @article{geng_huang_jin_song_chang_jameel_2014, title={Comparison of sodium carbonate-oxygen and sodium hydroxide-oxygen pretreatments on the chemical composition and enzymatic saccharification of wheat straw}, volume={161}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2014.03.024}, abstractNote={Pretreatment of wheat straw with a combination of sodium carbonate (Na2CO3) or sodium hydroxide (NaOH) with oxygen (O2) 0.5 MPa was evaluated for its delignification ability at relatively low temperature 110 °C and for its effect on enzymatic hydrolysis efficiency. In the pretreatment, the increase of alkali charge (as Na2O) up to 12% for Na2CO3 and 6% for NaOH, respectively, resulted in enhancement of lignin removal, but did not significantly degrade cellulose and hemicellulose. When the pretreated solid was hydrolyzed with a mixture of cellulases and hemicellulases, the sugar yield increased rapidly with the lignin removal during the pretreatment. A total sugar yield based on dry matter of raw material, 63.8% for Na2CO3–O2 and 71.9% for NaOH–O2 was achieved under a cellulase loading of 20 FPU/g-cellulose. The delignification efficiency and total sugar yield from enzymatic hydrolysis were comparable to the previously reported results at much higher temperature without oxygen.}, journal={BIORESOURCE TECHNOLOGY}, author={Geng, Wenhui and Huang, Ting and Jin, Yongcan and Song, Junlong and Chang, Hou-min and Jameel, Hasan}, year={2014}, month={Jun}, pages={63–68} }
 @article{yu_gwak_treasure_jameel_chang_park_2014, title={Effect of Lignin Chemistry on the Enzymatic Hydrolysis of Woody Biomass}, volume={7}, ISSN={["1864-564X"]}, DOI={10.1002/cssc.201400042}, abstractNote={Abstract}, number={7}, journal={CHEMSUSCHEM}, author={Yu, Zhiying and Gwak, Ki-Seob and Treasure, Trevor and Jameel, Hasan and Chang, Hou-min and Park, Sunkyu}, year={2014}, month={Jul}, pages={1942–1950} }
 @article{huo_li_zhang_fan_chang_jameel_2014, title={Effective C-O Bond Cleavage of Lignin beta-O-4 Model Compounds: A New RuHCl(CO)(PPh3)(3)/KOH Catalytic System}, volume={144}, ISSN={["1572-879X"]}, DOI={10.1007/s10562-014-1264-y}, number={7}, journal={CATALYSIS LETTERS}, author={Huo, Wei and Li, Wenzhi and Zhang, Minjian and Fan, Wei and Chang, Hou-min and Jameel, Hasan}, year={2014}, month={Jul}, pages={1159–1163} }
 @article{meng_geng_ren_jin_chang_jameel_2014, title={Enhancement of enzymatic saccharification of poplar by green liquor pretreatment}, volume={9}, DOI={10.15376/biores.9.2.3236-3247}, abstractNote={Green liquor (Na2S + Na2CO3, GL) pretreatment is an effective pathway for improving the enzymatic digestibility of lignocellulosic biomass for the production of bioethanol. In this work, GL was employed as a pretreatment to enhance the enzymatic saccharification of poplar. During pretreatment, the increase of H-factor and TTA charge resulted in enhanced delignification and increased degradation of polysaccharides. The sugar yield of enzymatic hydrolysis increased rapidly with increasing TTA charge in GL pretreatment, while the effect of different H-factors (from 400 to 800) on sugar yield was unnoticeable. The pretreated solid recovery was 75.5% at a lignin removal rate of 29.2% under optimized conditions of total titratable alkali (TTA) charge 20%, sulfidity 25%, and H-factor 400. The sugar yield of glucan, xylan, and total sugar of GL-pretreated poplar in enzymatic hydrolysis reached up to 89.9%, 65.5%, and 82.8%, respectively, at a cellulase loading of 40 FPU/g-cellulose.}, number={2}, journal={BioResources}, author={Meng, X. and Geng, W. H. and Ren, H. and Jin, Y. C. and Chang, H. M. and Jameel, H.}, year={2014}, pages={3236–3247} }
 @article{ertas_han_jameel_chang_2014, title={Enzymatic hydrolysis of autohydrolyzed wheat straw followed by refining to produce fermentable sugars}, volume={152}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2013.11.026}, abstractNote={Wheat straw was pretreated using an autohydrolysis process with different temperatures (160-200 °C) and times (10-20 min) in order to allow the recovery of hemicellulose in the filtrate and help open up the structure of the biomass for improved accessibility of enzymes during enzymatic hydrolysis. Autohydrolysis at 190 °C for 10 min provided the highest overall sugar (12.2/100g raw wheat straw) in the autohydrolysis filtrate and recovered 62.3% of solid residue. Before enzymatic hydrolysis, the pulps obtained from each pretreatment condition were subjected to a refining post-treatment to improve enzyme accessibility. Enzymatic hydrolysis was performed for all the pretreated solids with and without refining post-treatment at the enzyme loadings of 4 and 10 FPU/g oven dry substrate for 96 h. A total of 30.4 g sugars can be recovered from 100g wheat straw at 180 °C for 20 min with 4 FPU/g enzyme charge.}, journal={BIORESOURCE TECHNOLOGY}, author={Ertas, Murat and Han, Qiang and Jameel, Hasan and Chang, Hou-min}, year={2014}, month={Jan}, pages={259–266} }
 @article{min_xiang_liu_jameel_chiang_jin_chang_2014, title={Improved Protocol for Alkaline Nitrobenzene Oxidation of Woody and Non-Woody Biomass}, volume={35}, ISSN={0277-3813 1532-2319}, url={http://dx.doi.org/10.1080/02773813.2014.902965}, DOI={10.1080/02773813.2014.902965}, abstractNote={The protocol of alkaline nitrobenzene oxidation was investigated to improve its ability to identify the different lignin structures for both woody and non-woody biomass. The survival factors of all six oxidation products—syringaldehde (Sr), vanillin (V), p-hydroxybenzaldehyde (B) and their corresponding acids, syringic acid (Sa), vanillic acid (Va), and p-hydroxybenzoic acid (Ba)—were studied at 170, 180, and 190°C for several residence times. Under similar conditions, various lignin model compounds—a softwood (loblolly pine), a hardwood (red maple), and a non-wood raw material (corn stover)—were oxidized. Molar yields of oxidation products were determined and the ratios of (Sr+Sa)/(V+Va), (Sr/V), and B/(V+Va) (B/V) were calculated. All oxidation products were relatively stable at 170 and 180°C but showed some degradation at 190°C, especially at long residence time. In all cases, p-hydroxybenzoic acid was barely detectable. While yields of oxidation products reach a maximum at 170°C for pine and maple, maximal yields of corn stover require 190°C. Consequently, we recommend that nitrobenzene oxidation be carried out at 170°C for 2.5 h for softwood and hardwood, but at 190°C and 4 h with correction for the survival factors for corn stover and other non-woody biomass. Alternatively, a protocol of oxidation at two temperatures is recommended for non-woody biomass.}, number={1}, journal={Journal of Wood Chemistry and Technology}, publisher={Informa UK Limited}, author={Min, Douyong and Xiang, Zhouyang and Liu, Jie and Jameel, Hasan and Chiang, Vincent and Jin, Yongcan and Chang, Hou-min}, year={2014}, month={Sep}, pages={52–61} }
 @article{li_li_hu_zu_wang_jameel_chang_2014, title={Pretreatment of corn stover for sugar production by a two-step process using dilute hydrochloric acid followed by aqueous ammonia}, volume={9}, DOI={10.15376/biores.9.3.4622-4635}, abstractNote={A novel two-step process for pretreatment of corn stover was investigated with the goal of increasing sugar recovery and decreasing the capital cost. In the process, corn stover was first treated with dilute hydrochloric acid to maximize xylan recovery, and then the residue was treated with aqueous ammonia to alter the lignin structure and swell the cellulose surface. The optimal conditions were 110 °C and 40 min for 1% dilute hydrochloric acid pretreatment with a liquid to solid ratio of 10:1 followed by aqueous ammonia pretreatment at 37% NH3, 130 °C, 30 min, and liquid to solid ratio of 6:1. Under these pretreatment conditions, the glucan and xylan recoveries were 83.2% and 97.3%, respectively, with cellulase dosage at 15 FPU/g of substrate. When the cellulase dosage was decreased from 15 FPU/g to 10 FPU/g of substrate, the glucan recovery only dropped to 70%, while the xylan recovery remained high at 95.1%. The results show that this two-step pretreatment was effective for achieving high sugar recovery from corn stover by enzymatic hydrolysis.}, number={3}, journal={BioResources}, author={Li, Z. H. and Li, W. Z. and Hu, H. P. and Zu, S. and Wang, Z. Y. and Jameel, H. and Chang, H. M.}, year={2014}, pages={4622–4635} }
 @article{zu_li_zhang_li_wang_jameel_chang_2014, title={Pretreatment of corn stover for sugar production using dilute hydrochloric acid followed by lime}, volume={152}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2013.11.034}, abstractNote={In this study, a two stage process was evaluated to increase the sugar recovery. Firstly, corn stover was treated with diluted hydrochloric acid to maximize the xylose yield, and then the residue was treated with lime to alter the lignin structure and swell the cellulose surface. The optimal condition was 120 °C and 40 min for diluted hydrochloric acid pretreatment followed by lime pretreatment at 60 °C for 12h with lime loading at 0.1 g/g of substrate. The glucose and xylose yield was 78.0% and 97.0%, respectively, with cellulase dosage at 5 FPU/g of substrate. The total glucose yield increased to 85.9% when the cellulase loading was increased to 10 FPU/g of substrate. This two stage process was effective due to the swelling of the internal surface, an increase in the porosity and a decrease in the degree of polymerization.}, journal={BIORESOURCE TECHNOLOGY}, author={Zu, Shuai and Li, Wen-zhi and Zhang, Mingjian and Li, Zihong and Wang, Ziyu and Jameel, Hasan and Chang, Hou-min}, year={2014}, month={Jan}, pages={364–370} }
 @article{wu_jameel_chang_phillips_2014, title={Techno-economic analysis of the optimum softwood lignin content for the production of bioethanol in a repurposed kraft mill}, volume={9}, DOI={10.15376/biores.9.4.6817-6830}, abstractNote={Kraft pulping is one possible pretreatment for softwood to economically produce bioethanol. This work evaluates the techno-economic potential of using the kraft process for producing bioethanol from softwoods in a repurposed or co-located kraft mill. Pretreated loblolly pine was enzymatically hydrolyzed at low enzyme dosages of 5 and 10 FPU/g of substrate. Pretreated residue with 13% lignin content had the highest sugar recovery, 32.7% and 47.7% at 5 and 10 FPU/g, respectively. The pretreated residues were oxygen delignified and refined. In all cases, oxygen delignification improved sugar recovery, while refining was mostly effective for pulps with high lignin content. At 5 FPU/g, the sugar recovery for all kraft pulps was 51 to 53% with oxygen delignification and refining. Increasing the enzyme dosage to 10 FPU/g increased the sugar recovery for these pulps to greater than 60%. Economic analysis for the pulps with different initial lignin content showed that kraft pulps with an initial lignin content of 6.7% with oxygen delignification had an ethanol yield of 285 L/ODt wood and the lowest total production cost of $0.55/L. Pulps with initial lignin content of 18.6% had a total production cost of $0.64/L with an ethanol yield of 264 L/ODt wood.}, number={4}, journal={BioResources}, author={Wu, S. F. and Jameel, H. and Chang, H. M. and Phillips, R.}, year={2014}, pages={6817–6830} }
 @article{min_yang_chiang_jameel_chang_2014, title={The influence of lignin-carbohydrate complexes on the cellulase-mediated saccharification II: Transgenic hybrid poplars (Populus nigra L. and Populus maximowiczii A.)}, volume={116}, ISSN={["1873-7153"]}, DOI={10.1016/j.fuel.2013.07.046}, abstractNote={Twelve transgenic hybrid poplars (Populus nigra L. and Populus maximowiczii A.) were used to demonstrate the influence of the lignin–carbohydrate complexes (LCCs) on enzymatic saccharification. The samples have different levels of the syringaldehyde (S) to vanillin (V) ratio from 0.1 to 2.6 and the lignin content from 10.5% to 24.3%, compared to the control (the S/V ratio 1.7 and the lignin content 22.0%). Any adventitious contaminants that could affect the final enzymatic saccharification were removed by performing thorough extraction on the samples. The crude milled wood lignins were subsequently isolated from which the phenyl glycoside, benzyl ether and γ-ester linkages representative of the LCC were identified and quantified by 13C and 1H–13C HSQC NMR. It was found that the samples showed different levels of the three LCC linkages, depending on the lignin content and/or the S/V ratio. The correlation between the LCCs and enzymatic saccharification nearly conclusively demonstrated that the LCCs accounted for the recalcitrance of lignocellulosic biodegradation.}, journal={FUEL}, author={Min, Dou-yong and Yang, Chenmin and Chiang, Vincent and Jameel, Hasan and Chang, Hou-min}, year={2014}, month={Jan}, pages={56–62} }
 @article{min_jameel_chang_lucia_wang_jin_2014, title={The structural changes of lignin and lignin-carbohydrate complexes in corn stover induced by mild sodium hydroxide treatment}, volume={4}, ISSN={["2046-2069"]}, DOI={10.1039/c3ra47032f}, abstractNote={Non-woody biomass such as corn stover is a very abundant and sustainable biofuel feedstock in the US whose technical hurdles for enzymatic hydrolysis have not been adequately addressed. There is very little useful data on the lignin and the lignin–carbohydrate complexes of corn stover and the impacts of them on bioconversion to fermentable sugars. The following principal tasks were addressed, which will help to develop the roadmap of effective saccharification of corn stover: (1) corn stover was separated into stem, cob, and leaf; (2) lignin (cellulolytic enzyme lignin, CEL) and lignin–carbohydrate complexes (milled wood lignin, MWLc) were isolated from the extractive-free and the alkaline-treated samples, respectively; and (3) the structural changes of lignin and lignin–carbohydrate complexes (LCCs) were characterized by alkaline nitrobenzene oxidation, 13C, and 1H–13C HSQC NMR. The results indicated: (1) a significant amount of p-coumarate and ferulate esters was identified and quantified; (2) lignin of the alkaline-treated sample was more condensed; (3) an unanticipated amount of LCCs was quantified in the extractive-free sample, however, the amount of LCCs decreased significantly with the alkaline treatment. Therefore, lignin and LCCs of the treated sample should be characterized to elucidate their effects on the enzymatic saccharification.}, number={21}, journal={RSC ADVANCES}, author={Min, D. Y. and Jameel, H. and Chang, H. M. and Lucia, L. and Wang, Z. G. and Jin, Y. C.}, year={2014}, pages={10845–10850} }
 @article{min_chang_jameel_lucia_wang_jin_2014, title={The structure of lignin of corn stover and its changes induced by mild sodium hydroxide treatment}, volume={9}, DOI={10.15376/biores.9.2.2405-2414}, abstractNote={Corn stover is an abundant feedstock in the US that can be used for second generation bioethanol production. However, there is little useful data on structure of the lignin of corn stover. The following principal tasks will be addressed to profile the structure of corn stover: (1) separation of corn stover into stem, cob, and leaf; (2) isolation of cellulolytic enzyme lignins (CEL) from extractive-free and the alkali-treated fractions; (3) quantification of p-coumarate and ferulate of fractions by HPLC. The results of alkaline nitrobenzene oxidation and 1H-13C HSQC NMR indicated: (1) the structure of lignin varied in the fractions; (2) a remarkable amount of p-coumarate and ferulate was identified and determined; (3) the remarkable structural changes of lignin induced by alkaline treatment were elucidated.}, number={2}, journal={BioResources}, author={Min, D. Y. and Chang, H. M. and Jameel, H. and Lucia, Lucian and Wang, Z. G. and Jin, Y. C.}, year={2014}, pages={2405–2414} }
 @article{min_li_chiang_jameel_chang_lucia_2014, title={nnThe influence of lignin-carbohydrate complexes on the cellulase-mediated saccharification I: Transgenic black cottonwood (western balsam poplar, California poplar) P-trichocarpa including the xylan down-regulated and the lignin down-regulated lines}, volume={119}, ISSN={["1873-7153"]}, DOI={10.1016/j.fuel.2013.11.047}, abstractNote={The influence of the putative lignin–carbohydrate complexes (LCCs) on enzymatic saccharification was elucidated for the first time by examining two groups of transgenic black cottonwood (P. trichocarpa) comprised of the lignin down-regulated and the xylan down-regulated lines. Any adventitious contaminants that could affect the characterization of LCCs and the enzymatic saccharification were removed by performing a thorough extraction on the samples. The crude milled wood lignin was subsequently isolated from which the phenyl glycoside, benzyl ether and γ-ester linkages representative of the LCCs were identified and quantified with the combination of 13C and 1H–13C Heteronuclear Single Quantum Coherence (HSQC) NMR. The result indicated that the samples showed different levels of the three LCC linkages, depending on the xylan and/or lignin content. The correlation between the LCCs and enzymatic saccharification nearly conclusively demonstrated that the LCCs accounting for the recalcitrance of lignocellulosic biodegradation.}, journal={FUEL}, author={Min, Dou-yong and Li, Quanzi and Chiang, Vincent and Jameel, Hasan and Chang, Hou-min and Lucia, Lucian}, year={2014}, month={Mar}, pages={207–213} }
 @article{chi_chang_li_jameel_zhang_2013, title={A method for rapid determination of sugars in lignocellulose prehydrolyzate}, volume={8}, DOI={10.15376/biores.8.1.172-181}, abstractNote={A simple and rapid dual-wavelength spectroscopic method is used for simultaneous determination of pentoses and hexoses in the prehydrolyzate from lignocellulosic biomass. The method is based on the following reaction mechanism: in the solution of hydrochloric acid, phloroglucinol gives color reaction with sugars or their degradation products, showing maximum absorbance at 553 nm and 410 nm. Based on dual-wavelength spectrophotometric measurement, the pentoses and hexoses can separately be quantified. It was found that the derivatives from these two different sugars have an isosbestic point at 425 nm. According to the validation results, high accuracy and reasonable recovery rate is shown with the present method (pentoses recovery 97.1 to 100.0%, hexoses recovery 97.2 to 102.0%). Additionally, the interferences from substances including lignin, furfural, 5-hydroxymethyl furfural (HMF), glucuronic acid, and galacturonic acid are insignificant. All of the above results illustrate the suitability of this method for analyzing sugars in the lignocelluloses prehydrolyzate, especially hardwoods or herbaceous plants, based on forest-related biorefinery research.}, number={1}, journal={BioResources}, author={Chi, C. C. and Chang, H. M. and Li, Z. J. and Jameel, H. and Zhang, Z.}, year={2013}, pages={172–181} }
 @article{ayoub_venditti_jameel_chang_2013, title={Effect of irradiation on the composition and thermal properties of softwood kraft lignin and styrene grafted lignin}, volume={131}, ISSN={0021-8995}, url={http://dx.doi.org/10.1002/APP.39743}, DOI={10.1002/app.39743}, abstractNote={ABSTRACT}, number={1}, journal={Journal of Applied Polymer Science}, publisher={Wiley}, author={Ayoub, Ali and Venditti, Richard A. and Jameel, Hasan and Chang, Hou-Min}, year={2013}, month={Jul}, pages={n/a-n/a} }
 @article{longue_ayoub_venditti_jameel_colodette_chang_2013, title={Ethanol precipitation of hetero-polysaccharide material from hardwood by alkaline extraction prior to the Kraft cooking process}, volume={8}, DOI={10.15376/biores.8.4.5319-5332}, abstractNote={Hemicellulose material is an abundant and relatively under-utilized hetero-polysaccharide material present in lignocellulosic materials. In this study, an alkaline treatment was applied to sweetgum and Eucalyptus globulus chips to extract hemicelluloses prior to kraft pulping to subsequently evaluate the final product and process. An alkaline extraction (10 and 50% NaOH by weight on wood) for 60 min at 100 °C followed by precipitation in ethanol recovered 4.3% of the biomass as a predominantly xylan material (sweetgum 50% NaOH) with an average degree of polymerization around 250 and functional groups similar to a commercial xylan (sweetgum 10% NaOH). This process in comparison to autohydrolysis (water extraction at 100 °C) produced a much higher molecular weight and more pure hemicellullose. The results obtained indicate a promising combination between the effective extraction of hemicellulose from wood and a distillation process that recovers the ethanol, which may be an attractive alternative to recover liquor and ethanol after hemicellulose precipitation. Hemicellulose from sweetgum showed more thermal stability with high molecular weight compared to the hemicellulose extracted from Eucalyptus globulus. An attractive alternative looks to be to recover liquor and ethanol after hemicellulose precipitation.}, number={4}, journal={BioResources}, author={Longue, D. and Ayoub, A. and Venditti, Richard and Jameel, H. and Colodette, J. L. and Chang, H. M.}, year={2013}, pages={5319–5332} }
 @article{santos_jameel_chang_hart_2013, title={Impact of lignin and carbohydrate chemical structures on degradation reactions during hardwood kraft pulping processes}, volume={8}, DOI={10.15376/biores.8.1.158-171}, abstractNote={Most studies aimed at determining rates of hardwood delignification and carbohydrate degradation have focused on understanding the behavior of a single wood species. Such studies tend to determine either the delignification rate or the rate of carbohydrate degradation without examining the potential interactions resulting from related variables. The current study provides a comprehensive evaluation on both lignin and carbohydrate degradation during kraft pulping of multiple hardwood species. The kraft delignification rates of E. urograndis, E. nitens, E. globulus, sweet gum, maple, red oak, red alder, cottonwood, and acacia were obtained. Furthermore, the kinetics of glucan, xylan, and total carbohydrate dissolution during the bulk phase of the kraft pulping process for the above species were also investigated. The wide ranges of delignification and carbohydrate degradation rates were correlated to wood chemical characteristics. It appears that the S/G ratio and lignin-carbohydrate-complexes (LCCs) are the main characteristics responsible for the differences in kraft pulping performance among the hardwoods studied.}, number={1}, journal={BioResources}, author={Santos, R. B. and Jameel, H. and Chang, H. M. and Hart, P. W.}, year={2013}, pages={158–171} }
 @article{min_smith_chang_jameel_2013, title={Influence of isolation condition on structure of milled wood lignin characterized by quantitative c-13 nuclear magnetic resonance spectroscopy}, volume={8}, DOI={10.15376/biores.8.2.1790-1800}, abstractNote={Milled wood lignin (MWL) was widely characterized to demonstrate the structure of native lignin by liquid state 13C NMR. As an isolated lignin, the structure of MWL was influenced by the isolation procedure performed. In this article, hardwood (sweetgum) and softwood (loblolly pine) were subjected to various isolation conditions to elucidate the effect of extracting temperature and milling time on the structure of MWL. Purification was also carried out on the crude MWL. The structure of the crude MWL and the purified MWL was identified and quantified by 13C NMR. Based on the yield and the lignin content of the crude MWL, the optimal isolation was achieved with 8 h milling and 20 °C extracting for hardwood. For softwood, the optimal isolation condition for crude MWL was 12 h milling and 20 °C extracting.}, number={2}, journal={BioResources}, author={Min, D. Y. and Smith, S. W. and Chang, H. M. and Jameel, H.}, year={2013}, pages={1790–1800} }
 @article{phillips_jameel_chang_2013, title={Integration of pulp and paper technology with bioethanol production}, volume={6}, ISSN={["1754-6834"]}, DOI={10.1186/1754-6834-6-13}, abstractNote={Despite decades of work and billions of dollars of investments in laboratory and pilot plant projects, commercial production of cellulosic ethanol is only now beginning to emerge. Because of: (1)high technical risk coupled with; (2) high capital investment cost relative to ethanol product value, investors have not been able to justify moving forward with large scale projects on woody biomass.Both issues have been addressed by targeting pulp and paper industry processes for application in bioethanol production, in Greenfield, Repurpose and Co-Location scenarios. Processes commercially proven in hundreds of mills for many decades have been tailored to the recalcitrance of the biomass available. Economically feasible cellulosic bioethanol can be produced in Greenfield application with hardwoods, but not softwoods, using kraft mill equipment. Both types of wood species can profitably produce ethanol when kraft mill or newsprint assets are Repurposed to a biorefinery. A third situation which can generate high financial returns is where excess kraft pulp is available at a mill which has no excess drying capacity. Each scenario is supported by laboratory simulation, engineering and financial analysis. While pretreatment is critical to providing access of the biomass to enzymes, capital investment per unit of ethanol produced can be attractive, even if ethanol yield is modest.Three guiding principles result in attractive economics: (1) re-use existing assets to the maximum extent; (2) keep the process as simple as possible; (3) match the recalcitrance of the biomass with the severity of the pretreatment.}, journal={BIOTECHNOLOGY FOR BIOFUELS}, author={Phillips, Richard B. and Jameel, Hasan and Chang, Hou Min}, year={2013}, month={Jan} }
 @article{yu_jameel_chang_philips_park_2013, title={Quantification of bound and free enzymes during enzymatic hydrolysis and their reactivities on cellulose and lignocellulose}, volume={147}, ISSN={0960-8524}, url={http://dx.doi.org/10.1016/j.biortech.2013.08.010}, DOI={10.1016/j.biortech.2013.08.010}, abstractNote={Enzymatic hydrolysis of insoluble biomass is a surface reaction. Part of the enzyme adsorb on the surface of biomass, whereas the others stay in the liquid phase. In this study, three substrates (Avicel cellulose, bleached hardwood pulp, and green-liquor pretreated hardwood pulp) were used to study the reactivity of bound and free enzyme. In a continuous enzymatic hydrolysis, 35-65% initially added enzymes became bound enzymes, which were primarily responsible for enzymatic hydrolysis. The contribution from free enzymes became insignificant after a certain period of reaction time. SDS-PAGE analysis showed that CBH I was significantly decreased in the free enzyme, which might be the reason for the low digestibility of free enzymes due to the loss of synergistic effect. When Tween 80 was added during enzymatic hydrolysis, the digestibility of free enzyme on Avicel was greatly enhanced. However, the benefit of surfactant was not noticeable for lignocellulosic pulps, comparing to Avicel.}, journal={Bioresource Technology}, publisher={Elsevier BV}, author={Yu, Zhiying and Jameel, Hasan and Chang, Hou-min and Philips, Richard and Park, Sunkyu}, year={2013}, month={Nov}, pages={369–377} }
 @article{jin_yang_jameel_chang_phillips_2013, title={Sodium sulfite-formaldehyde pretreatment of mixed hardwoods and its effect on enzymatic hydrolysis}, volume={135}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2012.09.073}, abstractNote={In this work, mixed hardwoods were pretreated by sodium sulfite-formaldehyde (SF). The effects of SF pretreatment on the chemical compositions and enzymatic hydrolysis of mixed hardwoods were investigated. SF pretreatment temperature had a significant effect on pulp yield and delignification, resulting in an increased efficiency of enzymatic hydrolysis. After 96 h of enzymatic hydrolysis at the cellulase loading of 40 FPU/g substrate, the yields of glucan and xylan on the basis of original wood were 37% and 11% for the pulp produced with 12% sulfite charge at 170 °C for 2 h. The total sugar recovery based on the sugar in original wood was 74%. These results indicate that sulfite-formaldehyde cooking is of great potential to be a pretreatment method for a greenfield mill to produce fuel ethanol from hardwood.}, journal={BIORESOURCE TECHNOLOGY}, author={Jin, Yongcan and Yang, Linfeng and Jameel, Hasan and Chang, Hou-min and Phillips, Richard}, year={2013}, month={May}, pages={109–115} }
 @article{min_yang_shi_jameel_chiang_chang_2013, title={The elucidation of the lignin structure effect on the cellulase-mediated saccharification by genetic engineering poplars (Populus nigra L. x Populus maximowiczii A.)}, volume={58}, ISSN={["1873-2909"]}, DOI={10.1016/j.biombioe.2013.08.019}, abstractNote={The lignin structure effect on the recalcitrance of biomass degradation was elucidated by twelve transgenic hybrid poplars (Populus nigra L. and Populus maximowiczii A.). Samples have different levels of the syringaldehyde (S) to vanillin (V) ratio from 0.1 to 2.6 and the lignin content from 10.5 to 24.3%, compared to the control (the S to V ratio 1.7 and the lignin content 22.0%). The dilute acid (0.1% sulfuric acid, 185 °C, and 30 min) and the green liquor (6% total titratable alkali (TTA), 25% sulfidity based on TTA, 185 °C and 15 min) were used as pretreatments. The enzymatic saccharification was performed at 5 FPU g−1 based on the substrate. The removal of lignin and hemicelluloses varied with pretreatments. The high delignification originated from the high S to V ratio. However, the high S to V ratio retarded the enzymatic saccharification. The decrease of the lignin and the hemicelluloses benefited the enzymatic saccharification with or without the pretreatment.}, journal={BIOMASS & BIOENERGY}, author={Min, Douyong and Yang, Chenmin and Shi, Rui and Jameel, Hasan and Chiang, Vincent and Chang, Houmin}, year={2013}, month={Nov}, pages={52–57} }
 @article{santos_hart_jameel_chang_2013, title={Wood based lignin reactions important to the biorefinery and pulp and paper industries}, volume={8}, DOI={10.15376/biores.8.1.1456-1477}, abstractNote={The cleavage of lignin bonds in a wood matrix is an important step in the processes employed in both the biorefinery and pulp and paper industries. β-O-4 ether linkages are susceptible to both acidic and alkaline hydrolysis. The cleavage of α-ether linkages rapidly occurs under mildly acidic reaction conditions, resulting in lower molecular weight lignin fragments. Acidic reactions are typically employed in the biorefinery industries, while alkaline reactions are more typically employed in the pulp and paper industries, especially in the kraft pulping process. By better understanding lignin reactions and reaction conditions, it may be possible to improve silvicultural and breeding programs to enhance the formation of easily removable lignin, as opposed to more chemically resistant lignin structures. In hardwood species, the S/G ratio has been successfully correlated to the amount of β-O-4 ether linkages present in the lignin and the ease of pulping reactions.}, number={1}, journal={BioResources}, author={Santos, R. B. and Hart, P. W. and Jameel, H. and Chang, H. M.}, year={2013}, pages={1456–1477} }
 @article{wu_chang_jameel_philips_2012, title={Effect of Additives on Polysaccharide Retention in Green Liquor Pretreatment of Loblolly Pine for Enzymatic Hydrolysis}, volume={32}, ISSN={["1532-2319"]}, DOI={10.1080/02773813.2012.678959}, abstractNote={Abstract In order to improve polysaccharide retention during pretreatment and increase enzymatic hydrolysis efficiency, green liquor (GL) pretreatment was performed at: (1) higher GL sulfidity; (2) higher sulfidity with the addition of sodium polysulfide; (3) higher sulfidity with the addition of sodium borohydride; or (4) higher sulfudity with the addition of sodium tetraborate. The results indicate that green liquor pretreatment with the higher sulfidity, with the addition of polysulfide and with the addition of sodium borohydride, is effective in increasing enzymatic conversion of the pretreated pulps. The addition of sodium tetraborate, on the other hand, is not effective. These measures can be combined with oxygen delignification and/or mechanical refining to further improve the enzymatic hydrolysis efficiency. Up to 80% of the polysaccharides in softwood can be converted to fermentable sugars, but only with the addition of 40 FPU enzyme dose.}, number={4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Wu, Shu-Fang and Chang, Hou-Min and Jameel, Hasan and Philips, Richard}, year={2012}, pages={317–327} }
 @article{yang_cao_jin_chang_jameel_phillips_li_2012, title={Effects of sodium carbonate pretreatment on the chemical compositions and enzymatic saccharification of rice straw}, volume={124}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2012.08.041}, abstractNote={The effects of sodium carbonate (Na2CO3) pretreatment on the chemical compositions and enzymatic saccharification of rice straw were investigated. The enzymatic digestibility of rice straw is enhanced after pretreatment since pretreated solids show significant delignification with high sugar availability. During pretreatment, an increasing temperature and Na2CO3 charge leads to enhanced delignification, whereas an increased degradation of polysaccharides as well, of which xylan acts more susceptible than glucan. The sugar recovery of enzymatic hydrolysis goes up rapidly with the total titratable alkali (TTA) increasing from 0% to 8%, and then it reaches a plateau. The highest sugar recovery of rice straw after pretreatment, 71.7%, 73.2%, and 76.1% for total sugar, glucan, and xylan, respectively, is obtained at 140 °C, TTA 8% and cellulase loading of 20 FPU/g-cellulose. In this condition, the corresponding delignification ratio of pretreated solid is 41.8%, while 95% of glucan and 76% of xylan are conserved.}, journal={BIORESOURCE TECHNOLOGY}, author={Yang, Linfeng and Cao, Jie and Jin, Yongcan and Chang, Hou-min and Jameel, Hasan and Phillips, Richard and Li, Zhongzheng}, year={2012}, month={Nov}, pages={283–291} }
 @article{yu_jameel_chang_philips_park_2012, title={Evaluation of the factors affecting avicel reactivity using multi-stage enzymatic hydrolysis}, volume={109}, DOI={10.1002/bit.24386}, abstractNote={Abstract}, number={5}, journal={Biotechnology and Bioengineering}, author={Yu, Z. Y. and Jameel, H. and Chang, H. M. and Philips, R. and Park, Sunkyu}, year={2012}, pages={1131–1139} }
 @article{giles_peszlen_peralta_chang_farrell_grand_horvath_2012, title={Fungal biodegradation of genetically modified and lignin-altered quaking aspen (Populus tremuloides Michx.)}, volume={66}, ISSN={["0018-3830"]}, DOI={10.1515/hf.2011.144}, abstractNote={Abstract}, number={1}, journal={HOLZFORSCHUNG}, author={Giles, Richard and Peszlen, Ilona and Peralta, Perry and Chang, Hou-Min and Farrell, Roberta and Grand, Larry and Horvath, Balazs}, year={2012}, month={Jan}, pages={105–110} }
 @article{gu_yang_jin_han_chang_jameel_phillips_2012, title={Green liquor pretreatment for improving enzymatic hydrolysis of corn stover}, volume={124}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2012.08.054}, abstractNote={Green liquor consists of sodium carbonate and sodium sulfide and is readily available in any kraft mills. The green liquor pretreatment process for bioethanol production was developed for wood chips. This process uses only proven technology and equipment currently used in a kraft pulp mill and has several additional advantages such as high sugar recovery and concentration, no inhibitive substances produced, as compared to acid-based pretreatment methods. The liquor was used to pretreat corn stover for enhancing enzymatic hydrolysis in bioethanol production. Pulp yield of 70% with 45% lignin removal was achieved under optimized conditions (8% total titratable alkali, 40% sulfidity and 140 °C). About 70% of the original polysaccharides were converted into fermentable sugars, using 20 FPU/g-pulp of enzyme in the subsequent enzymatic hydrolysis. The result indicates that green liquor is a feasible pretreatment to improve the enzymatic saccharification of corn stover for bioethanol production.}, journal={BIORESOURCE TECHNOLOGY}, author={Gu, Feng and Yang, Linfeng and Jin, Yongcan and Han, Qiang and Chang, Hou-min and Jameel, Hasan and Phillips, Richard}, year={2012}, month={Nov}, pages={299–305} }
 @article{santos_treasure_gonzalez_phillips_lee_jameel_chang_2012, title={Impact of hardwood species on production cost of second generation ethanol}, volume={117}, ISSN={["1873-2976"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84861134453&partnerID=MN8TOARS}, DOI={10.1016/j.biortech.2012.04.083}, abstractNote={The present work targeted the understanding of the influence of nine different hardwood species as feedstock on ethanol production yield and costs. It was found that the minimum ethanol revenue (MER) ($ per gallon to the producer) to achieve a 12% internal rate of return (IRR) on invested capital was smaller for low lignin content samples and the influence of species characteristics remained restricted to high residual lignin content. We show that if the pretreatment being applied to the feedstock targets or is limited to low lignin removal, one can expect the species to have a significant impact on overall economics, playing important role to project success. This study also showed a variation of up to 40% in relative MER among hardwood species, where maple, globulus and sweet gum varied the least. Sensitivity analysis showed ethanol yield per ton of feedstock had the largest influence in MER, followed by CAPEX.}, journal={BIORESOURCE TECHNOLOGY}, author={Santos, Ricardo B. and Treasure, Trevor and Gonzalez, Ronalds and Phillips, Richard and Lee, Jung Myoung and Jameel, Hasan and Chang, Hou-min}, year={2012}, month={Aug}, pages={193–200} }
 @article{santos_jameel_chang_harts_2012, title={Kinetics of Hardwood Carbohydrate Degradation during Kraft Pulp Cooking}, volume={51}, ISSN={["0888-5885"]}, DOI={10.1021/ie301071n}, abstractNote={Most of the studies on hardwood carbohydrate degradation focus upon the understanding of carbohydrate behavior of a single wood species. These studies tend to determine the activation energies associated with the three different cooking phases and for the different reactions that participate in carbohydrate degradation. In the current study, a variety of hardwood species were comprehensively characterized and the kinetics of carbohydrate degradation was studied. The kinetics of glucan, xylan, and total carbohydrate dissolution during the bulk phase of the kraft pulping process were investigated. A wide range of carbohydrate dissolution rates was obtained and correlated to chemical features and delignification rates for nine different hardwood species. It was determined that carbohydrate dissolution was dependent upon the rate of delignification. Species with high carbohydrate dissolution also presented high lignin removal rates. Our results indicate that the presence of lignin carbohydrate complexes positively influences pulping process selectivity during the bulk reaction phase.}, number={38}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Santos, Ricardo B. and Jameel, Hasan and Chang, Hou-min and Harts, Peter W.}, year={2012}, month={Sep}, pages={12192–12198} }
 @article{santos_capanema_balakshin_chang_jameel_2012, title={Lignin Structural Variation in Hardwood Species}, volume={60}, ISSN={["1520-5118"]}, DOI={10.1021/jf301276a}, abstractNote={A comprehensive lignin structure analysis of ten industrially relevant hardwood species is presented. Milled wood lignin (MWL) was isolated from each species using a modified protocol and all milled wood lignin preparations were analyzed through quantitative (13)C NMR spectroscopy, elemental analysis, methoxyl analysis, sugar analysis, and nitrobenzene oxidation. Nitrobenzene oxidation and ozonation were carried out on extractive-free wood, alkali-extracted wood, milled wood lignin, and alkali-extracted lignin. Milled wood lignin isolated by the modified protocol was found to be representative of the total lignin in alkali-extracted wood. Significant variations in lignin structures, such as syringylpropane/guaiacylpropane ratio (S/G ratio), arylglycerol-β-aryl ether (β-O-4), degree of condensation, and elemental and methoxyl contents, were found among the hardwood species studied. These structural variations among species appear to be correlated to a single factor, the syringyl/guaiacyl ratio. A new method to predict the S/G ratio of total lignin in wood was developed, using a calibration line established by the syringaldehyde/vanillin (S/V) ratio (nitrobenzene oxidation) and the S/G ratio ((13)C NMR) of milled wood lignin (MWL).}, number={19}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Santos, Ricardo B. and Capanema, Ewellyn A. and Balakshin, Mikhail Yu and Chang, Hou-min and Jameel, Hasan}, year={2012}, month={May}, pages={4923–4930} }
 @article{xue_jameel_phillips_chang_2012, title={Split addition cif enzymes in enzymatic hydrolysis at high solids concentration to increase sugar concentration for bioethanol production}, volume={18}, ISSN={["1876-794X"]}, DOI={10.1016/j.jiec.2011.11.132}, abstractNote={One challenge in making bioethanol production economical is to increase total solids in hydrolysis system while maintaining sugar conversion efficiency. Because the removal of excess water from hydrolysate requires enormous amounts of heat, large volume of reaction towers and high capital expenditure (CAPEX) for equipment, a lengthy operating time, and high operating costs. When solids loading in hydrolysis system increased from 5% to 20% with no mixing strategies, final sugar conversion decreased markedly. If cellulase is mixed with pulp at 5% solids and pressed to 20% solids, then 80% of the cellulase retained in the pulp thinned down the pulp mixture in 2 h. This thinning effect enabled additional cellulase, xylanase, and β-glucosidase to be mixed into the slurry. Sugar concentration was significantly improved; from 26 g/L to 121 g/L, while sugar conversion was remained as enzymatic hydrolysis with 5% total solids enzymatic hydrolysis. A US patent has been granted to NCSU for this concept and licenses have been granted to various companies.}, number={2}, journal={JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY}, author={Xue, Ying and Jameel, Hasan and Phillips, Richard and Chang, Hou-min}, year={2012}, month={Mar}, pages={707–714} }
 @article{min_li_jameel_chiang_chang_2012, title={The Cellulase-Mediated Saccharification on Wood Derived from Transgenic Low-Lignin Lines of Black Cottonwood (Populus trichocarpa)}, volume={168}, ISSN={["1559-0291"]}, DOI={10.1007/s12010-012-9833-2}, abstractNote={Downregulated lignin transgenic black cottonwood (Populus trichocarpa) was used to elucidate the effect of lignin and xylan content on enzymatic saccharification. The lignin contents of three transgenic samples (4CL1-1, 4CL1-4, and CH8-1-4) were 19.3, 16.7, and 15.0 %, respectively, as compared with the wild type (21.3 %). The four pretreatments were dilute acid (0.1 % sulfuric acid, 185 °C, 30 min), green liquor (6 % total titratable alkali, 25 % sulfidity based on TTA, 185 °C, and 15 min.), autohydrolysis (185 °C, 30 min), and ozone delignification (25 °C, 30 min). Following the pretreatment, enzymatic saccharification was carried out using an enzyme charge of 5 FPU/g of substrates. The removal of lignin and hemicellulose varies with both the types of pretreatments and the lignin content of the transgenic trees. Due to the greatest removal of lignin, green liquor induced the highest sugar production and saccharification efficiency, followed by acid, ozone, and autohydrolysis in descending order. The results indicated that lignin is the main recalcitrance of biomass degradation. At a given lignin content, pretreatment with ozone delignification had lower saccharification efficiency than the other pretreatment methods due to higher xylan content.}, number={4}, journal={APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY}, author={Min, Douyong and Li, Quanzi and Jameel, Hasan and Chiang, Vincent and Chang, Hou-min}, year={2012}, month={Oct}, pages={947–955} }
 @inproceedings{min_li_yang_chang_chiang_jameel_2012, title={The effects of transgenic samples on the enzymatic saccharification}, booktitle={Proceeding of the 4th International Conference on Pulping, Papermaking and Biotechnology (ICPPB '12), vols. I and II}, author={Min, D. Y. and Li, Q. Z. and Yang, C. M. and Chang, H. M. and Chiang, V. and Jameel, H.}, year={2012}, pages={1058–1062} }
 @inproceedings{yu_gwak_chang_park_jameel_2012, title={The impact of lignin on enzymatic hydrolysis of lignocellulosic biomass}, booktitle={Proceeding of the 4th International Conference on Pulping, Papermaking and Biotechnology (ICPPB '12), vols. I and II}, author={Yu, Z. Y. and Gwak, K. S. and Chang, H. M. and Park, S. and Jameel, H.}, year={2012}, pages={1143–1147} }
 @article{min_jameel_chiang_chang_2012, title={effect of lignin on enzymatic saccharification of hardwood after green liquor and sulfuric acid pretreatments}, volume={7}, DOI={10.15376/biores.7.2.2272-2283}, abstractNote={Red maple, sweet gum, trembling aspen, red alder, and Eucalyptus globulus samples were pretreated with dilute sulfuric acid and green liquor before enzymatic saccharification. Substrates showed different levels of delignification and sugar recovery, depending on the applied pretreatments and the syringaldehyde/vanillin ratio (S/V). Three major conclusions were drawn in this research. First, lignin is the greatest contributor to recalcitrance of hardwood to enzymatic saccharification. Second, a high S/V ratio is a useful indicator of high delignification during a pretreatment process. Third, green liquor pretreatment is a promising pretreatment method because of a high delignification degree and sugar recovery. In addition, xylan also contributes to the recalcitrance of hardwoods toward enzymatic saccharification.}, number={2}, journal={BioResources}, author={Min, D. Y. and Jameel, H. and Chiang, V. and Chang, H. M.}, year={2012}, pages={2272–2283} }
 @article{min_li_jameel_chiang_chang_2011, title={Comparison of pretreatment protocols for cellulase-mediated saccharification of wood derived from transgenic low-xylan lines of cottonwood (P. trichocarpa)}, volume={35}, ISSN={["1873-2909"]}, DOI={10.1016/j.biombioe.2011.04.034}, abstractNote={The novel low xylan content transgenic cottonwood (P. trichocarpa) was used to elucidate recalcitrance of enzymatic saccharification with or without four different pretreatment methods. The xylan contents of two transgenic samples (8Di3 and 8Di5) were 11.4% and 11.7%, respectively, as compared with the wild type (16.0%). Contrarily, the lignin contents of two transgenic samples were 23.1% and 24.5%, respectively, as compared with the wild type (20.8%). The four pretreatments were dilute acid (0.1% sulfuric acid, 185 °C, 30 min), green liquor (6% total titratable alkali (TTA), 25% sulfidity based on TTA, 185 °C and 15 min), auto hydrolysis (185 °C, 30 min) and ozone delignification (25 °C, 30 min). Following the pretreatment, enzymatic saccharification was carried out using three enzyme charges of 10, 20 and 30 FPU per gram of substrate. The removal of lignin and hemicelluloses varied with the type of pretreatment and with the lignin content of the transgenic trees. High lignin content implied low enzymatic saccharification. Low xylan content native substrates lead to high enzymatic saccharification. High S to V (sryingaldehyde to vanillin) ratio substrates had high delignification during pretreatment. Compared to the wild type, the transgenics were better choice as feed stocks due to higher enzymatic saccharification without pretreatment which mean low the cost of bio-ethanol. Compared to three pretreatment methods, the green liquor pretreatment greatly improves the conversion of polysaccharides in general.}, number={8}, journal={BIOMASS & BIOENERGY}, author={Min, Douyong and Li, Quanzi and Jameel, Hasan and Chiang, Vincent and Chang, Hou-min}, year={2011}, month={Aug}, pages={3514–3521} }
 @article{li_min_wang_peszlen_horvath_horvath_nishimura_jameel_chang_chiang_2011, title={Down-regulation of glycosyltransferase 8D genes in Populus trichocarpa caused reduced mechanical strength and xylan content in wood}, volume={31}, ISSN={["1758-4469"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79953831391&partnerID=MN8TOARS}, DOI={10.1093/treephys/tpr008}, abstractNote={Members of glycosyltransferase protein families GT8, GT43 and GT47 are implicated in the biosynthesis of xylan in the secondary cell walls of Arabidopsis. The Arabidopsis mutant irx8 has a 60% reduction in xylan. However, over-expression of an ortholog of Arabidopsis IRX8, poplar PoGT8D, in Arabidopsis irx8 mutant could not restore xylan synthesis. The functions of tree GT8D genes remain unclear. We identified two GT8 gene homologs, PtrGT8D1 and PtrGT8D2, in Populus trichocarpa. They are the only two GT8D members and are abundantly and specifically expressed in the differentiating xylem of P. trichocarpa. PtrGT8D1 transcript abundance was >7 times that of PtrGT8D2. To elucidate the genetic function of GT8D in P. trichocarpa, the expression of PtrGT8D1 and PtrGT8D2 was simultaneously knocked down through RNAi. Four transgenic lines had 85-94% reduction in transcripts of PtrGT8D1 and PtrGT8D2, resulting in 29-36% reduction in stem wood xylan content. Xylan reduction had essentially no effect on cellulose quantity but caused an 11-25% increase in lignin. These transgenics exhibit a brittle wood phenotype, accompanied by increased vessel diameter and thinner fiber cell walls in stem xylem. Stem modulus of elasticity and modulus of rupture were reduced by 17-29% and 16-23%, respectively, and were positively correlated with xylan content but negatively correlated with lignin quantity. These results suggest that PtrGT8Ds play key roles in xylan biosynthesis in wood. Xylan may be a more important factor than lignin affecting the stiffness and fracture strength of wood.}, number={2}, journal={TREE PHYSIOLOGY}, publisher={Oxford University Press (OUP)}, author={Li, Quanzi and Min, Douyong and Wang, Jack Peng-Yu and Peszlen, Ilona and Horvath, Laszlo and Horvath, Balazs and Nishimura, Yufuko and Jameel, Hasan and Chang, Hou-Min and Chiang, Vincent L.}, year={2011}, month={Feb}, pages={226–236} }
 @misc{santos_capanema_balakshin_chang_jameel_2011, title={Effect of hardwoods characteristics on kraft pulping process: Emphasis on lignin structure}, volume={6}, number={4}, journal={BioResources}, author={Santos, R. B. and Capanema, E. A. and Balakshin, M. Y. and Chang, H. M. and Jameel, H.}, year={2011}, pages={3623–3637} }
 @article{balakshin_capanema_gracz_chang_jameel_2011, title={Quantification of lignin-carbohydrate linkages with high-resolution NMR spectroscopy}, volume={233}, ISSN={["0032-0935"]}, DOI={10.1007/s00425-011-1359-2}, abstractNote={A quantitative approach to characterize lignin-carbohydrate complex (LCC) linkages using a combination of quantitative ¹³C NMR and HSQC 2D NMR techniques has been developed. Crude milled wood lignin (MWLc), LCC extracted from MWLc with acetic acid (LCC-AcOH) and cellulolytic enzyme lignin (CEL) preparations were isolated from loblolly pine (Pinus taeda) and white birch (Betula pendula) woods and characterized using this methodology on a routine 300 MHz NMR spectrometer and on a 950 MHz spectrometer equipped with a cryogenic probe. Structural variations in the pine and birch LCC preparations of different types (MWL, CEL and LCC-AcOH) were elucidated. The use of the high field NMR spectrometer equipped with the cryogenic probe resulted in a remarkable improvement in the resolution of the LCC signals and, therefore, is of primary importance for an accurate quantification of LCC linkages. The preparations investigated showed the presence of different amounts of benzyl ether, γ-ester and phenyl glycoside LCC bonds. Benzyl ester moieties were not detected. Pine LCC-AcOH and birch MWLc preparations were preferable for the analysis of phenyl glycoside and ester LCC linkages in pine and birch, correspondingly, whereas CEL preparations were the best to study benzyl ether LCC structures. The data obtained indicate that pinewood contains higher amounts of benzyl ether LCC linkages, but lower amounts of phenyl glycoside and γ-ester LCC moieties as compared to birch wood.}, number={6}, journal={PLANTA}, author={Balakshin, Mikhail and Capanema, Ewellyn and Gracz, Hanna and Chang, Hou-min and Jameel, Hasan}, year={2011}, month={Jun}, pages={1097–1110} }
 @article{koo_treasure_jameel_phillips_chang_park_2011, title={Reduction of enzyme dosage by oxygen delignification and mechanical refining for enzymatic hydrolysis of green liquor-pretreated hardwood}, volume={165}, DOI={10.1007/s12010-011-9301-4}, abstractNote={In this study, a strategy to reduce enzyme dosage is evaluated by applying two post-treatments, oxygen delignification and mechanical refining. The sugar conversion for GL12 substrates was increased from 51.5% to 77.9% with post-treatments at the enzyme dosage of 10 FPU. When the amount of enzyme was reduced to 5 FPU with post-treatments, the conversion of 71.8% was obtained, which was significant higher than the conversion without any post-treatment using 10 FPU (51.5%). This clearly demonstrates the benefit of post-treatments that allows more than 50% of enzyme reduction at the same level of enzymatic conversion. Enzyme-accessible surface area and pore volume were evaluated by Simons' staining and DSC thermoporometry methods, and strong correlations were found with the sugar conversion.}, number={3-4}, journal={Applied Biochemistry and Biotechnology}, author={Koo, B. W. and Treasure, T. H. and Jameel, H. and Phillips, R. B. and Chang, H. M. and Park, Sunkyu}, year={2011}, pages={832–844} }
 @article{su_ho_hsu_chang_farrell_wang_2011, title={Screening of Ophiostoma Species for Removal of Eucalyptus Extractives}, volume={31}, ISSN={["0277-3813"]}, DOI={10.1080/02773813.2010.523164}, abstractNote={Abstract Ophiostoma species have been demonstrated to metabolize wood extractives and be useful to the pulp and paper industry. In order to have new isolates for the Asian market, Eucalyptus camaldulensis logs were harvested from forest sites in central Taiwan and 28 strains of the Ophiostoma genus were isolated from them. These strains were subsequently inoculated onto Eucalyptus wood chips to evaluate their effects on weight losses of wood and the amounts of acetone extractives degraded. At the same time, Gas Chromatography-Mass Spectroscopy (GC-MS) analysis was conducted and by using calibration curves and a database of GC-MS mass spectra, changes in lipophilic compounds were analyzed. Fatty acids, hydrocarbons, sterol compounds, sterol esters, and triglycerides were significantly reduced after two weeks’ inoculation by the fungal strains. The results show that six of the strains were capable of reducing the lipophilic fractions by more than 60% in a two-week treatment. DNA of the most effective strains were analyzed and found to be a variant of Ophiostoma querci.}, number={4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Su, Yu-Chang and Ho, Chen-Lung and Hsu, Kuang-Ping and Chang, Hou-Min and Farrell, Roberta and Wang, Eugene I-Chen}, year={2011}, pages={282–297} }
 @article{yu_jameel_chang_park_2011, title={The effect of delignification of forest biomass on enzymatic hydrolysis}, volume={102}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2011.07.001}, abstractNote={The effect of delignification methods on enzymatic hydrolysis of forest biomass was investigated using softwood and hardwood that were pretreated at an alkaline condition followed by sodium chlorite or ozone delignification. Both delignifications improved enzymatic hydrolysis especially for softwood, while pretreatment alone was found effective for hardwood. High enzymatic conversion was achieved by sodium chlorite delignification when the lignin content was reduced to 15%, which is corresponding to 0.30–0.35 g/g accessible pore volume, and further delignification showed a marginal effect. Sample crystallinity index increased with lignin removal, but it did not show a correlation with the overall carbohydrate conversion of enzymatic hydrolysis.}, number={19}, journal={BIORESOURCE TECHNOLOGY}, author={Yu, Zhiying and Jameel, Hasan and Chang, Hou-min and Park, Sunkyu}, year={2011}, month={Oct}, pages={9083–9089} }
 @article{gonzalez_jameel_chang_treasure_pirraglia_saloni_2011, title={Thermo-mechanical pulping as a pretreatment for agricultural biomass for biochemical conversion}, volume={6}, number={2}, journal={BioResources}, author={Gonzalez, R. and Jameel, H. and Chang, H. M. and Treasure, T. and Pirraglia, A. and Saloni, D.}, year={2011}, pages={1599–1614} }
 @article{jin_jameel_chang_phillips_2010, title={Green Liquor Pretreatment of Mixed Hardwood for Ethanol Production in a Repurposed Kraft Pulp Mill}, volume={30}, ISSN={["1532-2319"]}, DOI={10.1080/02773810903578360}, abstractNote={Abstract The development of a new, relatively simple process, which uses green liquor (sodium carbonate and sodium sulfide) as a pretreatment for the production of ethanol is described in this article. The pulps produced by this process can be enzymatically hydrolyzed to monomeric sugars with a high overall sugar recovery. The use of green liquor for pretreatment ensures that the chemicals used during pretreatment can be recovered efficiently using proven technology and can be easily implemented in a repurposed kraft pulp mill. The yield of pulps produced by the green liquor pretreatment process is about 80% with nearly 100% cellulose and 75% xylan in retention in mixed southern hardwood. The low pH prevents the random hydrolysis of polysaccharide and secondary peeling reactions from occurring during the pretreatment, resulting in higher retention of the polysaccharides in pulp. About 35% of the lignin is removed during the green liquor pretreatment process, which is sufficient for efficient enzymatic hydrolysis. The amount of sugar produced in enzymatic hydrolysis increased with both the green liquor and enzyme charge. The increase in enzymatic hydrolysis efficiency was small as the total titrateable alkali was increased beyond 12–16%. With green liquor pretreatment at 16% Total Titrateable Alkali (TTA), the overall sugar recovery for hardwood was shown to be around 77% at a cellulase charge of 20 FPU/gm of substrate. A sugar recovery of 80% could be achieved at higher enzyme charges. These levels of sugar recovery are competitive with other pretreatments for hardwood. This novel pretreatment process can be used to repurpose kraft mills, which are being closed due to a decrease in the demand for paper in North America, for production of ethanol.}, number={1}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Jin, Yongcan and Jameel, Hasan and Chang, Hou-min and Phillips, Richard}, year={2010}, pages={86–104} }
 @article{chi_zhang_chang_jameel_2009, title={Determination of Furfural and Hydroxymethylfurfural Formed From Biomass Under Acidic Conditions}, volume={29}, ISSN={["0277-3813"]}, DOI={10.1080/02773810903096025}, abstractNote={Abstract A rapid method for simultaneous determination of furfural and hydroxymethylfurfural (HMF) in the filtrate of an acidic treatment of biomass was developed based on UV spectrophotometer. Interference from acid soluble lignin is alleviated by the use of absorbance difference spectrum before and after reduction with sodium borohydride (NaBH4). The concentrations of furfural and HMF in the filtrate are determined by measuring the absorbance of the difference spectrum at 277 nm and 285 nm, the characteristic absorption maxima for furfural and HMF, respectively. Two simultaneous equations are solved to obtain the concentrations of furfural and HMF in the filtrate. Acid soluble lignin in the solution is determined to cause negligible interference on the analysis.}, number={4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Chi, Congcong and Zhang, Zeng and Chang, Hou-min and Jameel, Hasan}, year={2009}, pages={265–276} }
 @article{wang_yokoyama_chang_matsumoto_2009, title={Dissolution of beech and spruce milled woods in LiCl/DMSO}, volume={57}, DOI={10.1021/jf900441q}, abstractNote={A novel solvent system, lithium chloride/dimethyl sulfoxide (LiCl/DMSO), was developed for dissolving milled wood. This system completely dissolved beech and spruce milled woods prepared from the Wiley woods (coarse wood meals prepared by a Wiley mill) by 2 h planetary ball-milling under the milling conditions employed. The dependence of the structural change of lignin on the degree of milling was examined to evaluate the correlation between the dissolution and lignin structure. The nitrobenzene oxidation analyses showed that the 2 h milling caused almost no structural change in the aromatic part of lignin in the milled woods. The ozonation analyses suggested that the decrease of the erythro ratio [erythro/(erythro + threo)] obtained from beta-O-4 structure in lignin is only 0.35% after the 2 h milling. Although the yield decrease of the ozonation products was 9.8% after the 2 h milling, this value was fairly smaller than that after a longer time milling. When it is taken into consideration that the other solvent systems for dissolution of wood meal, which are proposed by Lu and Ralph, require 5 h of milling under the same milling conditions to dissolve the milled woods, it is safely stated that the LiCl/DMSO solvent system completely dissolves milled wood, the lignin of which is structurally less altered and, thus, is expected to provide an improved method for structural analysis of the entire lignin fraction in wood cell wall.}, number={14}, journal={Journal of Agricultural and Food Chemistry}, author={Wang, Z. G. and Yokoyama, T. and Chang, H. M. and Matsumoto, Y.}, year={2009}, pages={6167–6170} }
 @article{kim_chang_kadla_2008, title={Polyoxometalate (POM) oxidation of lignin model compounds}, volume={62}, ISSN={["0018-3830"]}, DOI={10.1515/HF.2008.006}, abstractNote={Abstract}, number={1}, journal={HOLZFORSCHUNG}, author={Kim, Yong Sik and Chang, Hou-min and Kadla, John F.}, year={2008}, pages={38–49} }
 @article{holtman_chang_kadla_2007, title={An NMR comparison of the whole lignin from milled wood, MWL, and REL dissolved by the DMSO/NMI procedure}, volume={27}, ISSN={["1532-2319"]}, DOI={10.1080/02773810701700828}, abstractNote={Abstract Lignins isolated from pine milled wood, milled wood lignin (MWL), and residual enzyme lignin (REL) were compared using modified thioacidolysis, modified DFRC, gel permeation chromatography (GPC), two‐dimensional Heteronuclear Multiple Quantum Coherence (HMQC) NMR, and quantitative 13C NMR. Dissolution of the lignin for solution‐state NMR was accomplished by utilizing the recently reported DMSO/N‐methylimidazole/acetic anhydride solvent system. Contrary to previous reports, comparison of the lignin preparations by thioacidolysis indicated that REL was more structurally similar to the lignin in the milled wood and Wiley wood meal than MWL. Total monomer yields indicated that the MWL was lower in β‐aryl ether content than the other preparations, and this was verified by quantitative 13C NMR. NMR analysis indicated that the inter‐unit linkages present in all the lignin preparations are consistent with the present knowledge about lignin biosynthesis. The contribution of minor end group structures in the MWL are further decreased in the milled wood, indicating that they are preferentially isolated as low molecular weight material, possibly generated during the milling process. All other structural moieties were similar in all preparations. GPC data indicated that the milled wood and REL both contain a portion of lignin with a molecular weight of 55,000 g/mol. Data indicate that the inefficiency of the DFRC method may be related to molecular mobility or accessibility in higher molecular weight portions of the lignin polymer.}, number={3-4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Holtman, Kevin M. and Chang, Hou-Min and Kadla, John F.}, year={2007}, pages={179–200} }
 @article{balakshin_capanema_chang_2007, title={MWL fraction with a high concentration of lignin-carbohydrate linkages: Isolation and 2D NMR spectroscopic analysis}, volume={61}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2007.001}, abstractNote={Abstract}, number={1}, journal={HOLZFORSCHUNG}, author={Balakshin, Mikhail Yu. and Capanema, Ewellyn A. and Chang, Hou-min}, year={2007}, pages={1–7} }
 @article{chen_hu_chang_li_2007, title={Micro analytical methods for determination of compression wood content in loblolly pine}, volume={27}, ISSN={["1532-2319"]}, DOI={10.1080/02773810701700810}, abstractNote={Abstract All loblolly pine trees, especially the juvenile portion, contain various amounts of compression wood. The morphological, chemical, and papermaking properties of compression wood are distinctively different from those of normal juvenile wood and mature wood. Compression wood has higher lignin and galactan, but lower cellulose and mannan content, shorter average fiber length, lower fiber width but thicker cell wall, higher fiber coarseness and higher microfibril angles as compared with the corresponding normal wood. Micro analytical methods have been developed to quantitatively determine the percentage of compression wood in an incremental core so as to eliminate the effects of compression wood on the aforementioned properties. This enables accurate quantitative genetic analyses of these properties for tree breeding programs.}, number={3-4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Chen, Qing-min and Hu, Zhoujian and Chang, Hou-min and Li, Bailian}, year={2007}, pages={169–178} }
 @article{kim_chang_kadla_2007, title={Polyoxometalate (POM) oxidation of milled wood lignin (MWL)}, volume={27}, ISSN={["0277-3813"]}, DOI={10.1080/02773810701702188}, abstractNote={Abstract The chemical structural changes of Lodgepole pine milled wood lignin (MWL) before and after polyoxometalate (POM) oxidation were investigated using gel permeation chromatography (GPC), Fourier Transform infrared spectroscopy (FTIR), and solution‐state nuclear magnetic resonance spectroscopy (NMR). 13C NMR spectroscopic data revealed an approximately 28% decrease in α‐OH/β‐O‐4 inter‐unit linkages after POM treatment. This was accompanied by an increase in carbonyl and phenolic hydroxyl content. These results suggest POM oxidation involved side chain (such as α‐OH/β‐O‐4) oxidation and/or degradation of some of the inter‐unit linkages. Quantitative 13C NMR along with GPC analysis revealed an increase in the degree of condensation of the MWL as a result of POM treatment, suggesting radical coupling as a major reaction pathway.}, number={3-4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Kim, Yong Sik and Chang, Hou-min and Kadla, John F.}, year={2007}, pages={225–241} }
 @article{mazur_hope-ross_kadla_sederoff_chang_2007, title={Synthesis of hydroxyphenylpropanoid beta-D-glucosides}, volume={27}, ISSN={["0277-3813"]}, DOI={10.1080/02773810701282264}, abstractNote={Abstract Dihydroconiferyl alcohol glucoside has been synthesized from cinnamic acid ethyl ester glucoside. Two reaction systems were investigated; one involving hydrogenation of the cinnamic acid ethyl ester glucoside intermediate followed by diisobutylaluminium hydride (DIBAL‐H) reduction of the ester to the alcohol, and the other involving DIBAL‐H reduction of the cinnamic acid ethyl ester to the alcohol (coniferin) followed by hydrogenation. Hydrogenation followed by DIBAL‐H reduction led to higher dihydroconiferyl alcohol glucoside yields and avoided by‐product formation associated with the hydrogenation of coniferin.}, number={1}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Mazur, Magdalena and Hope-Ross, Kyle and Kadla, John F. and Sederoff, Ron and Chang, Hou-min}, year={2007}, pages={1–8} }
 @article{chang_kirkman_2006, title={A tribute to Prof. Josef S. Gratzl: Scientist, teacher, friend, May 24, 1929-December 2, 2004}, volume={26}, ISSN={["0277-3813"]}, DOI={10.1080/02773810600580248}, abstractNote={Josef S. Gratzl was a colleague, teacher, and friend to many in the Wood Chemistry and Paper Science fields. He touched and enhanced many lives through his passion for science and his zest for life. This memorial issue, compiled by his colleagues, honors his life and the achievements of his more than 40-year career. Journal of Wood Chemistry and Technology, 26: 1–4, 2006 Copyright # Taylor & Francis Group, LLC ISSN 0277-3813 print/1532-2319 online DOI: 10.1080/02773810600580248}, number={1}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Chang, HM and Kirkman, AG}, year={2006}, pages={1–4} }
 @article{hu_yeh_chang_matsumoto_kadla_2006, title={Elucidation of the structure of cellulolytic enzyme lignin}, volume={60}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2006.061}, abstractNote={Abstract}, number={4}, journal={HOLZFORSCHUNG}, author={Hu, Zhoujian and Yeh, Ting-Feng and Chang, Hou-min and Matsumoto, Yuji and Kadla, John F.}, year={2006}, month={Jul}, pages={389–397} }
 @article{sykes_li_isik_kadla_chang_2006, title={Genetic variation and genotype by environment interactions of juvenile wood chemical properties in Pinus taeda L.}, volume={63}, ISSN={["1286-4560"]}, DOI={10.1051/forest:2006073}, abstractNote={Genetic variation and genotype by environment interaction (G×E) were studied in several juvenile wood traits of 11 year-old loblolly pine trees (Pinus taeda L.). Wafer thin (200 µm) samples from juvenile (ring 3) and transition (ring 8) wood of 12 mm increment cores were analyzed. Transition wood had higher α-cellulose content (46.1%), longer fiber (1.98 mm), and higher coarseness (0.34), but lower lignin (29.7%) than juvenile wood (cellulose 40.9%, fiber length 1.4 mm, coarseness 0.28 and lignin 30.3%). General combining ability variance for the traits explained 2% to 10% of the total variance, whereas the specific combining ability variance was negligible, except for α-cellulose content in transition wood (2%). Specific combining ability by site interaction variance explained from 5% (fiber length) to 37% (lignin) of the total variance. Weak individual-tree heritabilities were found for all the traits, except coarseness, which was moderately high in both juvenile (0.39) and transition wood (0.30). Full-sib and half-sib family heritabilities of traits ranged 0.29 to 0.72. Genetic correlations of wood quality traits with volume and stem straightness were weak, while favorable genetic correlations of lignin with cellulose, coarseness and fiber length were observed. Implications on forest tree improvement programs were discussed. heritability / genetic correlation / α-cellulose / coarseness / lignin}, number={8}, journal={ANNALS OF FOREST SCIENCE}, publisher={EDP Sciences}, author={Sykes, Robert and Li, Bailian and Isik, Fikret and Kadla, John and Chang, H. -M.}, year={2006}, month={Dec}, pages={897–904} }
 @article{svenson_jameel_chang_kadla_2006, title={Inorganic reactions in chlorine dioxide bleaching of softwood kraft pulp}, volume={26}, ISSN={["0277-3813"]}, DOI={10.1080/02773810601023255}, abstractNote={Abstract A softwood kraft pulp (27 kappa) was bleached with chlorine dioxide to various end pH values. The formation of chlorite, chlorate, and chloride was measured to quantify the amount of chlorine dioxide wasted as a function of pH during a Do (pre‐bleaching) stage. Chlorate formation increased with a decrease in final pH. Conversely, residual chlorite increased with an increase in the final pH. After 120 min of bleaching the total residual chlorite and chlorate showed that no substantial increase in residual oxidant occurs when bleaching to an end pH below 3.4. As a result, the brightness and permanganate numbers for low pH chlorine dioxide bleached pulps did not differ when bleaching to an end pH between 3.4 and 1.8. However, decreasing the pH below 3.4 did result in increased organic chloride formation. The results are contrary to previous studies where the maximum bleaching efficiency for a D1 stage was reported to occur when the end pH was between 3 and 4.}, number={3}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Svenson, Douglas R. and Jameel, Hasan and Chang, Hou-min and Kadla, John F.}, year={2006}, pages={201–213} }
 @article{yeh_braun_goldfarb_chang_kadla_2006, title={Morphological and chemical variations between juvenile wood, mature wood, and compression wood of loblolly pine (Pinus taeda L.)}, volume={60}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2006.001}, abstractNote={Abstract}, number={1}, journal={HOLZFORSCHUNG}, author={Yeh, TF and Braun, JL and Goldfarb, B and Chang, HM and Kadla, JF}, year={2006}, month={Jan}, pages={1–8} }
 @article{dai_jameel_chang_2006, title={Precipitation of extractives onto kraft pulps during black liquor recycling in extended delignification process}, volume={26}, ISSN={["0277-3813"]}, DOI={10.1080/02773810600582210}, abstractNote={Abstract Our objective was to study the extractives content and the bleachability of batch extended delignified kraft pulps during the black liquor recycling. Extractives accumulated in the black liquor during the black liquor recycling. Some of the extractives in the black liquor precipitated on the pulps in the pretreatment stage, which affected the bleachability of pulps. For softwood, after 5 stages of black liquor recycling, the extractive content of the kraft pulps increased by up to 4 times and the final brightness decreased up to 2.4% ISO. The amount of extractives precipitating on the pulps strongly depended on the final pH of the pretreatment black liquor, which was determined by the operating conditions such as sulfidity, alkali charge, and pretreatment temperature. High alkalinity and low pretreatment temperature was the most efficient combination to minimize extractives from precipitating, and to maintain high bleachability of the kraft pulps. For hardwood, large amounts of extractives precipitated onto fibers, and the extractive content, especially the neutral extractive content, of the hardwood kraft pulps was high. During the black liquor recycling, the drop of the final brightness of hardwood kraft pulps was larger than that of the softwood kraft pulps.}, number={1}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Dai, QZ and Jameel, H and Chang, HM}, year={2006}, pages={35–51} }
 @article{holtman_chang_jameel_kadla_2006, title={Quantitative C-13 NMR characterization of milled wood lignins isolated by different milling techniques}, volume={26}, ISSN={["1532-2319"]}, DOI={10.1080/02773810600582152}, abstractNote={Abstract Milled wood lignins (MWL) prepared from finely milled wood flour produced by different milling techniques were compared by quantitative 13C NMR. Wood meal produced in a Wiley mill was milled for either six weeks in a porcelain rotary mill with porcelain balls, or by two variations of our standard technique. Specifically the Wiley wood meal was milled for one week in the rotary mill followed by 48 h of vibratory ball‐milling with steel balls either in toluene or under a N2 atmosphere. Results showed that the vibratory‐milled samples were similar in structure with the exception that the preparation milled under N2 had higher aliphatic and phenolic hydroxyl contents. The rotary‐milled sample on the other hand had a much lower β‐O‐4′ and hydroxyl content along with a higher degree of condensation and oxidized side chain structures.}, number={1}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Holtman, KM and Chang, HM and Jameel, H and Kadla, JF}, year={2006}, pages={21–34} }
 @article{yamada_yeh_chang_li_kadla_chiang_2006, title={Rapid analysis of transgenic trees using transmittance near-infrared spectroscopy (NIR)}, volume={60}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2006.005}, abstractNote={Abstract}, number={1}, journal={HOLZFORSCHUNG}, author={Yamada, T and Yeh, TF and Chang, HM and Li, LG and Kadla, JF and Chiang, VL}, year={2006}, month={Jan}, pages={24–28} }
 @article{yeh_morris_goldfarb_chang_kadla_2006, title={Utilization of polar metabolite profiling in the comparison of juvenile wood and compression wood in loblolly pine (Pinus taeda)}, volume={26}, ISSN={["0829-318X"]}, DOI={10.1093/treephys/26.11.1497}, abstractNote={Juvenile wood (JW) of conifers is often associated with compression wood (CW), with which it is sometimes believed to be identical. To determine whether JW and CW can be distinguished metabolically, we compared gas chromatographic profiles of 25 polar metabolites from rooted cuttings of a single loblolly pine (Pinus taeda L.) clone raised in controlled environment chambers and subject to three treatments: (1) grown erect with minimal wind sway (control); (2) swayed by wind from oscillating fans; and (3) with 30-cm growth increments successively bent at an angle of 45 degrees to the vertical. Profiles were compared by principal component analysis. Substantial increases in abundances of coniferin and p-glucocoumaryl alcohol separated immature JW-forming xylem tissues of the control trees from the CW-forming xylem of the bent and swayed trees.}, number={11}, journal={TREE PHYSIOLOGY}, author={Yeh, Ting-Feng and Morris, Cameron R. and Goldfarb, Barry and Chang, Hou-Min and Kadla, John F.}, year={2006}, month={Nov}, pages={1497–1503} }
 @article{yeh_goldfarb_chang_peszlen_braun_kadla_2005, title={Comparison of morphological and chemical properties between juvenile wood and compression wood of loblolly pine}, volume={59}, ISSN={["1437-434X"]}, DOI={10.1515/hf.2005.107}, abstractNote={Abstract}, number={6}, journal={HOLZFORSCHUNG}, author={Yeh, TF and Goldfarb, B and Chang, HM and Peszlen, I and Braun, JL and Kadla, JF}, year={2005}, pages={669–674} }
 @article{sykes_li_hodge_goldfarb_kadla_chang_2005, title={Prediction of loblolly pine wood properties using transmittance near-infrared spectroscopy}, volume={35}, ISSN={["1208-6037"]}, DOI={10.1139/X05-161}, abstractNote={ Near-infrared (NIR) spectroscopy is a rapid nondestructive technique that has been used to characterize chemical and physical properties of a wide range of materials. In this study, transmittance NIR spectra from thin wood wafers cut from increment cores were used to develop calibration models for the estimation of α-cellulose content, average fiber length, fiber coarseness, and lignin content in the laboratory. Eleven-year-old trees from two sites were sampled using 12-mm increment cores. Earlywood and latewood of ring 3 and ring 8 from these samples were analyzed in the laboratory using microanalytical methods for α-cellulose content, average fiber length, fiber coarseness, and lignin content. NIR calibrations and laboratory measurements based on one site were generally reliable, with coefficients of determination (R2) ranging from 0.54 to 0.88 for average fiber length and α-cellulose content, respectively. Predicting ring 8 properties using ring 3 calibration equations showed potential for predicting α-cellulose content and fiber coarseness, with R2 values of approximately 0.60, indicating the potential for early selection. Predicting the wood properties using the calibration equations from one site to predict another showed moderate success for α-cellulose content (R2 = 0.64) and fiber coarseness (R2 = 0.63), but predictions for fiber length were relatively poor (R2 = 0.43). Prediction of lignin content using transmittance NIR spectroscopy was not as reliable in this study, partially because of low variation in lignin content in these wood samples and large errors in measuring lignin content in the laboratory. }, number={10}, journal={CANADIAN JOURNAL OF FOREST RESEARCH}, author={Sykes, R and Li, BL and Hodge, G and Goldfarb, B and Kadla, J and Chang, HM}, year={2005}, month={Oct}, pages={2423–2431} }
 @article{fujimoto_matsumoto_chang_meshitsuka_2005, title={Quantitative evaluation of milling effects on lignin structure during the isolation process of milled wood lignin}, volume={51}, ISSN={["1611-4663"]}, DOI={10.1007/s10086-004-0682-7}, number={1}, journal={JOURNAL OF WOOD SCIENCE}, author={Fujimoto, A and Matsumoto, Y and Chang, HM and Meshitsuka, G}, year={2005}, pages={89–91} }
 @article{yeh_yamada_capanema_chang_chiang_kadla_2005, title={Rapid screening of wood chemical component variations using transmittance near-infrared spectroscopy}, volume={53}, ISSN={["1520-5118"]}, DOI={10.1021/jf0480647}, abstractNote={A rapid transmittance near-infrared (NIR) spectroscopy method was developed to predict the variation in chemical composition of solid wood. The effect of sample preparation, sample quantity (single versus stacked multiple wood wafers), and NIR acquisition time on the quantification of alpha-cellulose and lignin content was investigated. Strong correlations were obtained between laboratory wet chemistry values and the NIR-predicted values. In addition to the experimental protocol and method development, improvements in calibration error associated with utilizing stacked multiple wood wafers as opposed to single wood wafers are also discussed.}, number={9}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Yeh, TF and Yamada, T and Capanema, E and Chang, HM and Chiang, V and Kadla, JF}, year={2005}, month={May}, pages={3328–3332} }
 @article{svenson_chang_jameel_kadla_2005, title={The role of non-phenolic lignin in chlorate-forming reactions during chlorine dioxide bleaching of softwood kraft pulp}, volume={59}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2005.017}, abstractNote={Abstract}, number={2}, journal={HOLZFORSCHUNG}, author={Svenson, DR and Chang, HM and Jameel, H and Kadla, JF}, year={2005}, pages={110–115} }
 @inproceedings{morris_goldfarb_isik_li_chang_sederoff_kadla_2005, title={Variation of a-cellulose content and related metabolites during wood formation in loblolly pine}, volume={13}, booktitle={13th ISWFPC Proceedings}, author={Morris, C. R. and Goldfarb, B. and Isik, F. and Li, C. S. and Chang, H.-M. and Sederoff, R. and Kadla, J. F.}, year={2005} }
 @article{dai_jameel_chang_kadla_2004, title={Bleachability of kraft pulps from earlywood and latewood of fast-growing loblolly pine}, volume={24}, ISSN={["0277-3813"]}, DOI={10.1081/wct-200046256}, abstractNote={Abstract The pulping and bleaching properties of earlywood and latewood of a fast‐growing loblolly pine were studied. Under the same pulping condition, the kappa number of the latewood kraft pulp was higher than that of the earlywood. At around the same kappa number, the yield of the latewood was higher than that of the earlywood. The bleaching results showed that the latewood kraft pulp had lower bleachability than the earlywood kraft pulp, due to its thicker cell wall and slower leaching rate.}, number={4}, journal={JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY}, author={Dai, QZ and Jameel, H and Chang, HM and Kadla, JF}, year={2004}, pages={357–370} }
 @article{lemeune_jameel_chang_kadla_2004, title={Effects of ozone and chlorine dioxide on the chemical properties of cellulose fibers}, volume={93}, ISSN={["1097-4628"]}, DOI={10.1002/app.20509}, abstractNote={Abstract}, number={3}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Lemeune, S and Jameel, H and Chang, HM and Kadla, JF}, year={2004}, month={Aug}, pages={1219–1223} }
 @article{sykes_isik_li_kadla_chang_2004, title={Genetic variation in physiochemical wood properties in loblolly pine (Pinus taeda L.)}, volume={2}, number={12}, journal={TAPPI Journal}, author={Sykes, R. and Isik, F. and Li, B. and Kadla, J. and Chang, H.-M.}, year={2004}, pages={3–8} }
 @article{morris_scott_chang_sederoff_d o'malley_kadla_2004, title={Metabolic profiling: A new tool in the study of wood formation}, volume={52}, ISSN={["1520-5118"]}, DOI={10.1021/jf034688l}, abstractNote={In the realm of plant genomics, metabolic profiling has become a valuable tool with which to assess the effect of genetic and/or environmental factors on plant development. This paper reports the first application of metabolic profiling on differentiating xylem tissue of loblolly pine. A protocol is presented for the analysis of loblolly pine xylem tissue. The effects of sample preparation, extraction, and derivatization on the corresponding metabolite profiles and yields have been investigated and are reported. Gas chromatography-mass spectroscopy has been used to quantify >60 polar and lipophilic metabolites from wood-forming tissue. It was possible to assign chemical structures to approximately half of these compounds. Comparison of six loblolly pine genotypes, three high cellulose (50-52%) and three medium (45-48%) cellulose, showed distinct metabolic profiles. Principal component analysis enabled the assignment of metabolic phenotypes using these large data sets. Metabolic phenotype clustering occurred in which the three high-cellulose genotypes were segregated from the medium-cellulose genotypes. These results demonstrate the use of metabolic profiling for the study of wood-forming tissue and as a tool in functional genomics.}, number={6}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Morris, CR and Scott, JT and Chang, HM and Sederoff, RR and D O'Malley and Kadla, JF}, year={2004}, month={Mar}, pages={1427–1434} }
 @article{yokoyama_chang_reiner_atalla_weinstock_kadla_2004, title={Polyoxometalate oxidation of nonphenolic lignin subunits in water: Effect of substrate structure on reaction kinetics}, volume={58}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2004.016}, abstractNote={Summary}, number={2}, journal={HOLZFORSCHUNG}, author={Yokoyama, T and Chang, HM and Reiner, RS and Atalla, RH and Weinstock, IA and Kadla, JF}, year={2004}, pages={116–121} }
 @article{yeh_chang_kadla_2004, title={Rapid prediction of solid wood lignin content using transmittance near-infrared spectroscopy}, volume={52}, ISSN={["1520-5118"]}, DOI={10.1021/jf034874r}, abstractNote={A rapid transmittance near-infrared (NIR) spectroscopic method has been developed to characterize the lignin content of solid wood. Using simple, multiple regression, and partial least-squares statistical analysis the lignin contents of wood wafers, taken from increment cores, and synthetic wood, prepared by blending milled wood lignin and holocellulose, were compared and quantified. Strong correlations were obtained between the predicted NIR results and those obtained from traditional chemical methods. In addition to the experimental protocol and method development, NIR results from wood samples with different particle sizes and various lignin contents are discussed.}, number={6}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Yeh, TF and Chang, HM and Kadla, JF}, year={2004}, month={Mar}, pages={1435–1439} }
 @article{holtman_chang_kadla_2004, title={Solution-state nuclear magnetic resonance study of the similarities between milled wood lignin and cellulolytic enzyme lignin}, volume={52}, ISSN={["1520-5118"]}, DOI={10.1021/jf035084k}, abstractNote={The structures of milled wood lignin (MWL) and cellulolytic enzyme lignin (CEL) have been analyzed using traditional chemical methods and solution-state NMR techniques. Comparisons of the results obtained reveal that subtle differences exist between the two lignin preparations. Thioacidolysis produced higher monomer yields from CEL than MWL, suggesting MWL has a more condensed structure. Quantitative (13)C NMR determined the degree of condensation in MWL to be 0.43 unit per aromatic moiety as compared to 0.36 in CEL. The MWL also contained a lower amount of beta-O-4' substructures per aromatic ring than CEL, 0.41 versus 0.47, respectively. Carbohydrate analysis revealed that the MWL may contain a higher proportion of middle lamella material as compared to the CEL. Because the middle lamella is considered to have a more condensed lignin structure, on the basis of the bulk polymerization theory, these results could explain the differences in beta-O-4' and degree of condensation.}, number={4}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Holtman, KM and Chang, HM and Kadla, JF}, year={2004}, month={Feb}, pages={720–726} }
 @article{chen_heitmann_chang_hubbe_venditti_2004, title={The effect of paper additives on toner agglomeration during the recycling process}, volume={13}, number={14}, journal={Progress in Paper Recycling}, author={Chen, J. and Heitmann, J. A. and Chang, H.-M. and Hubbe, M. A. and Venditti, R. A.}, year={2004}, pages={16–23} }
 @inproceedings{yu_capanema_batista_josserand_johnson_nelson_mckeand_mackay_kadla_li_et al._2004, title={Tracking down the effects of a rare mutant gene in loblolly pine: a first report}, booktitle={2004 Paper Summit, Spring Technical and International Environmental Conference}, publisher={CD-ROM published by TAPPI,  Norcross, GA}, author={Yu, Q. and Capanema, E. and Batista, V. B. and Josserand, S. and Johnson, G. and Nelson, C. D. and McKeand, S. E. and MacKay, J. J. and Kadla, J. F. and Li, B. and et al.}, year={2004} }
 @article{zhu_chang_kadla_2003, title={A new method for the preparation of peroxymonophosphoric acid}, volume={81}, ISSN={["1480-3291"]}, DOI={10.1139/V03-010}, abstractNote={ A new method for the preparation of peroxymonophosphoric acid (H3PO5) has been developed. It utilizes a biphasic solution to moderate the vigorous reaction between phosphorous pentoxide (P2O5) and hydrogen peroxide (H2O2). P2O5 is suspended in carbon tetrachloride (CCl4), and concentrated H2O2 is slowly added while being vigorously stirred at low temperature. Careful control of the reaction temperature through the slow addition of H2O2 is critical. Using typical preparation conditions (P2O5:H2O2 = 0.5:1, H2O2 70 wt %, 2°C, 120–180 min), ~70% of the H2O2 is effectively converted to H3PO5. Increasing the concentration of H2O2, as well as the mole ratio of P2O5:H2O2, leads to an even higher % conversion of H2O2 to H3PO5. The addition of glacial acetic acid to the P2O5:H2O2 suspension at the end of the 120–180 min reaction (P2O5:H2O2:CH3COOH = 0.5:1:0.3) leads to the formation of peracetic acid in addition to H3PO5, and to an overall increase in the conversion ratio of total peroxy acids based on H2O2 (>95%).Key words: peroxymonophosphoric acid, synthesis, stability, conversion ratio. }, number={2}, journal={CANADIAN JOURNAL OF CHEMISTRY}, author={Zhu, T and Chang, HM and Kadla, JF}, year={2003}, month={Feb}, pages={156–160} }
 @article{holtman_chang_jameel_kadla_2003, title={Elucidation of lignin structure through degradative methods: Comparison of modified DFRC and thioacidolysis}, volume={51}, ISSN={["0021-8561"]}, DOI={10.1021/jf0340411}, abstractNote={Milled wood and milled wood lignin (MWL) samples were subjected to DFRC and thioacidolysis. Despite the fact that both methods selectively cleave aryl ether bonds, substantial differences in results were obtained. Lignin thioacidolysis gave total molar yields of degradation monomer products in the range of 3.5-7 mol % higher than DFRC. GPC analysis showed that the thioacidolysis-treated lignin was degraded to a lower average molecular weight than that treated by DFRC. Contrary to results reported for lignin model compounds, these results indicate that the DFRC method does not completely or efficiently degrade the lignin polymer. In fact, the DFRC-degraded lignin retained much of the characteristics of the original MWL. Elemental analysis revealed the presence of bromine in the DFRC-treated lignin, and two-dimensional (1)H-(13)C HMQC NMR spectroscopy showed the presence of beta-O-4 linkages in the DFRC-treated lignin. No beta-O-4 interunit linkages were detected in the thioacidolysis-treated lignin. These results are consistent with the lower monomer yields and the higher average molecular weight of the DFRC-treated lignin and indicate inefficiency in the chemistry of the method, probably due to steric constraints of the polymeric nature of lignin.}, number={12}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Holtman, KM and Chang, HM and Jameel, H and Kadla, JF}, year={2003}, month={Jun}, pages={3535–3540} }
 @article{sykes_isik_li_kadla_chang_2003, title={Genetic variation of juvenile wood properties in a loblolly pine progeny test}, volume={2}, number={12}, journal={TAPPI Journal}, author={Sykes, R. and Isik, F. and Li, B. L. and Kadla, J. and Chang, H. M.}, year={2003}, pages={08-} }
 @article{sykes_isik_li_kadla_chang_2003, title={Genetic variation of juvenile wood properties in loblolly pine diallel test}, volume={27}, journal={Proc. 27th Biennial Southern Forest Tree Improvement Conference}, author={Sykes, R. and Isik, F. and Li, B. and Kadla, J. and Chang, H-M.}, year={2003}, pages={27} }
 @article{zhu_kadla_chang_jameel_2003, title={Reactions of lignin with peroxymonophosphoric acid: The degradation of lignin model compounds}, volume={57}, ISSN={["0018-3830"]}, DOI={10.1515/HF.2003.007}, abstractNote={Summary}, number={1}, journal={HOLZFORSCHUNG}, author={Zhu, T and Kadla, JF and Chang, HM and Jameel, H}, year={2003}, pages={44–51} }
 @article{kishimoto_kadla_chang_jameel_2003, title={The reactions of lignin model compounds with hydrogen peroxide at low pH}, volume={57}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2003.008}, abstractNote={Summary}, number={1}, journal={HOLZFORSCHUNG}, author={Kishimoto, T and Kadla, JF and Chang, HM and Jameel, H}, year={2003}, pages={52–58} }
 @article{svenson_kadla_chang_jameel_2002, title={Effect of pH on the inorganic species involved in a chlorine dioxide reaction system}, volume={41}, DOI={10.1021/ie020191}, number={24}, journal={Industrial & Engineering Chemistry Research}, author={Svenson, D. R. and Kadla, J. F. and Chang, H. M. and Jameel, H.}, year={2002}, pages={5927–5933} }
 @article{svenson_kadla_chang_jameel_2002, title={Effect of pH on the mechanism of OClO center dot oxidation of aromatic compounds}, volume={80}, ISSN={["0008-4042"]}, DOI={10.1139/V02-089}, abstractNote={ Contrary to previous reports, the reaction mechanism of chlorine dioxide (OClO·) with benzyl alcohols involves both radical cation and benzyl radical mechanisms dependent on pH. The primary reaction product between OClO· and 1-(3,4-dimethoxy-phenyl) ethanol at pH 8 is 3,4-dimethoxyacetophenone. At pH 4 no acetophenone was observed; the majority of the degradation products were chlorinated and aromatic ring-oxidized compounds. A primary kinetic isotope effect (kH/kD = 2.05) was observed in the reaction of OClO· with 1-(3,4-dimethoxy-phenyl)-(1-2H) ethanol at pH 8, but was absent at pH 4 (kH/kD [Formula: see text] 1). Similarly, the corresponding methyl ether (4-(1-methoxy)ethyl-1,2-dimethoxybenzene) was substantially less reactive at pH > 6. On the basis of these results, competing pH-dependent reaction mechanisms have been proposed, where at high pH OClO· reacts with benzyl alcohols via a OClO·–benzyl alcohol complex.Key words: chlorine dioxide, mechanism, kinetic isotope effect, aromatic radical cation, benzyl radical. }, number={7}, journal={CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE}, author={Svenson, D and Kadla, JF and Chang, HM and Jameel, H}, year={2002}, month={Jul}, pages={761–766} }
 @article{yokoyama_kadla_chang_2002, title={Microanalytical method for the characterization of fiber components and morphology of woody plants}, volume={50}, ISSN={["0021-8561"]}, DOI={10.1021/jf011173q}, abstractNote={Microanalytical techniques were developed which allow the rapid characterization of fiber components and morphology of loblolly pine in a large number of samples. These techniques consist of extractives removal, holocellulose preparation, alpha-cellulose and lignin content determination, and fiber length and coarseness analyses. Greater than 95% of the nonvolatile extractives from an increment core sample of loblolly pine was removed by four successive two-day acetone extractions. Fiber morphology and alpha-cellulose content was determined from holocellulose prepared from only 100 mg of wood. Similarly, a microanalytical acetyl bromide method was developed that enabled the accurate determination of lignin content from less than 50 mg of wood. Through the development of these microanlytical methods, it is possible to accurately and rapidly analyze fiber morphology and chemical components in a large number of increment core samples.}, number={5}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Yokoyama, T and Kadla, JF and Chang, HM}, year={2002}, month={Feb}, pages={1040–1044} }
 @article{kadla_chang_2002, title={Reactions of lignin with cyanamide activated hydrogen peroxide Part 3. The degradation of pine kraft lignin}, volume={56}, ISSN={["1437-434X"]}, DOI={10.1515/HF.2002.013}, abstractNote={Summary}, number={1}, journal={HOLZFORSCHUNG}, author={Kadla, JF and Chang, HM}, year={2002}, pages={76–84} }
 @article{ikeda_holtman_kadla_chang_jameel_2002, title={Studies on the effect of ball milling on lignin structure using a modified DFRC method}, volume={50}, ISSN={["0021-8561"]}, DOI={10.1021/jf010870f}, abstractNote={The structures of milled wood lignin (MWL), cellulolytic enzyme lignin (CEL), and residual lignin (REL) from a loblolly pine were analyzed using a modified derivatization followed by reductive cleavage (DFRC) method developed to allow the quantitative determination of three different structural monomeric products originating in lignin: phenolic beta-O-4, alpha-O-4, and etherified beta-O-4 structures. Results show that MWL and CEL are structurally identical, with an increased phenolic beta-O-4 content compared to that of the original Wiley milled wood. These results indicate that the portion of lignin linked to carbohydrates and that not linked to carbohydrates are structurally the same. Modified DFRC analysis of the effect of ball milling on the structure of lignin in wood, MWL, CEL, and REL indicate that vibratory ball milling does not change the lignin structure provided certain precautions are taken. Specifically, dry vibratory ball milling under a nitrogen atmosphere causes substantial structural changes including condensation, whereas vibratory ball milling in toluene had little effect on the lignin structure. This indicates that the structural differences observed in MWL and CEL arise because of the extraction procedure, which preferentially extracts phenolic lignin structures. MWL and CEL are representative of the total lignin in wood; however, due primarily to the solvent extraction process, higher phenolic hydroxyl contents are observed. Nitrobenzene oxidation showed structural results similar to those from the modified DFRC method.}, number={1}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Ikeda, T and Holtman, K and Kadla, JF and Chang, HM and Jameel, H}, year={2002}, month={Jan}, pages={129–135} }
 @inproceedings{o'malley_scott_harkins_kadia_mckeand_chang_2001, title={Cinnamyl alcohol dehydrogenase (cad) and genomic approaches to manipulating wood properties in loblolly pine}, booktitle={7th Brazilian Symposium on the Chemistry of Lignins and Other Wood Components}, author={O'Malley, D. and Scott, J. and Harkins, D. and Kadia, J. and McKeand, S. and Chang, H-M}, year={2001}, pages={19–24} }
 @article{huo_venditti_chang_2001, title={Effect of cationic polymers, salts and fibres on the stability of model micro-stickies.}, volume={27}, number={6}, journal={Journal of Pulp and Paper Science}, author={Huo, X. and Venditti, R. A. and Chang, H. M.}, year={2001}, month={Jun}, pages={207–212} }
 @inproceedings{jameel_robison_chang_mcmurray_2001, title={Pulping of short rotation sycamore coppice to maximize productivity}, number={CD-ROM}, booktitle={Proceedings of the TAPPI Pulping Conference}, publisher={Seattle, WA: TAPPI Press}, author={Jameel, H. and Robison, D. and Chang, H. and McMurray, J.}, year={2001} }
 @article{chang_1999, title={Economic outlook for Asia's pulp and paper industry}, volume={82}, number={1}, journal={TAPPI Journal}, author={Chang, H. M.}, year={1999}, pages={50–52} }
 @article{venditti_chang_jameel_1999, title={Overview of stickies research at North Carolina State University}, number={1999 Nov.}, journal={Paper Age}, author={Venditti, R. A. and Chang, H. M. and Jameel, H.}, year={1999}, pages={18–20} }
 @inbook{venditti_chang_gilbert_1999, place={Appleton, WI}, title={Stickies measurement based on deposition used at North Carolina State University}, volume={IV}, booktitle={Paper Recycling Challenge: Process Control & Mensuration}, publisher={Progress in Paper Recycling}, author={Venditti, R.A. and Chang, H. M. and Gilbert, R. D.}, editor={Doshi, E.M. and Dyer, J.Editors}, year={1999}, pages={103–104} }
 @article{kadla_chang_jameel_1999, title={The reactions of lignins with high temperature hydrogen peroxide - Part 2. The oxidation of kraft lignin}, volume={53}, ISSN={["0018-3830"]}, DOI={10.1515/HF.1999.047}, abstractNote={Summary}, number={3}, journal={HOLZFORSCHUNG}, author={Kadla, JF and Chang, HM and Jameel, H}, year={1999}, pages={277–284} }
 @article{kadla_chang_chen_gratzl_1998, title={Reactions of lignin with cyanamide activated hydrogen peroxide Part 1. The degradation of lignin model compounds}, volume={52}, ISSN={["1437-434X"]}, DOI={10.1515/hfsg.1998.52.5.506}, abstractNote={Monomeric lignin model compounds representing various functional groups found in residual lignins were reacted with cyanamide activated hydrogen peroxide. Non-phenolic lignin model compounds failed to react even under extreme reaction conditions (90°C), while phenolic lignin model compounds underwent rapid oxidation. Reaction optimization studies reveal that these reactions are strongly dependent on pH and the cyanamide-to-peroxide ratio, while temperature is not a factor. Through the use of electron paramagnetic resonance (EPR) spectroscopy free radical involvement has been demonstrated. In contrast to previous literature, a predominately free-radical mechanism exists, and on the basis of the reactions carried out in the presence of superoxide dismutase, the presence of .O 2 - has been determined.}, number={5}, journal={HOLZFORSCHUNG}, author={Kadla, JF and Chang, PM and Chen, CL and Gratzl, JS}, year={1998}, pages={506–512} }
 @article{kadla_chang_chen_gratzl_1998, title={Reactions of lignin with cyanamide activated hydrogen peroxide Part 2. The degradation mechanism of phenolic lignin model compounds}, volume={52}, ISSN={["0018-3830"]}, DOI={10.1515/hfsg.1998.52.5.513}, abstractNote={The reactions of monomeric phenolic lignin model compounds with cyanamide activated hydrogen peroxide were studied. Analyses of the various reaction products indicate four main reactions occur : aromatic hydroxylation, demethoxylation, radical coupling and oxidative ring opening. The predominate products from apocynol and acetoguaiacone were dicarboxylic acid compounds, maleic/fumaric, oxalic and succinic acid derivatives, consistent with degradation by superoxide. In the degradation of creosol, 3-hydroxy-4-methoxy-6-methyl-N-methylaniline was the major compound isolated, providing evidence of a cyanamide radical. Finally, plausible pathways to the formation of superoxide anion and cyanamide oxidation products from alkaline hydrogen peroxide and cyanamide are proposed and their impact on delignification is discussed.}, number={5}, journal={HOLZFORSCHUNG}, author={Kadla, JF and Chang, HM and Chen, CL and Gratzl, JS}, year={1998}, pages={513–520} }
 @misc{chang_jameel_song_pan_amini_webster_evans_1997, title={Method of oxidatively treating a substrate with an equilibrium mixture of caro's acid and a percarboxylic acid}, volume={5,693,185}, number={1997 Dec. 2}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Chang, H.-M. and Jameel, H. and Song, J.-F. and Pan, D.-R. and Amini, B. and Webster, J. R. and Evans, B. A.}, year={1997} }
 @inbook{venditti_andrews_chang_heitmann_1997, place={Appleton, Wisc}, title={Stickies related research at North Carolina State University}, volume={1}, booktitle={Paper recycling challeng}, publisher={Doshi & Associates}, author={Venditti, R. A. and Andrews, E. K. and Chang, H.-M. and Heitmann, J. A.}, year={1997}, pages={45–49} }
 @article{kadla_chang_jameel_1997, title={The reactions of lignins with hydrogen peroxide at high temperature .1. The oxidation of lignin model compounds}, volume={51}, ISSN={["0018-3830"]}, DOI={10.1515/hfsg.1997.51.5.428}, abstractNote={This work deals with hydrogen peroxide bleaching at high temperature (90°) using simple phenolic and non-phenolic model compounds of the benzyl alcohol and benzaldehyde types. In addition to the reactions of the phenolic representatives, proceeding via the well known Dakin and Dakin-like mechanisms, the non-phenolic compounds are shown to react at these higher temperatures via an S N 2 mechanism to give ultimately the corresponding benzoic acids and a dimeric ether compound.}, number={5}, journal={HOLZFORSCHUNG}, author={Kadla, JF and Chang, HM and Jameel, H}, year={1997}, pages={428–434} }
 @misc{chang_wu_heitmann_1996, title={Deinking of xerographic printed wastepaper using long chain alcohol}, volume={5,500,082}, number={1996 Mar. 19}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Chang, H. M. and Wu, T. W. and Heitmann, J. A.}, year={1996} }
 @misc{chang_jameel_song_pan_amini_webster_evans_1996, title={Process for preparing a bleaching liquor containing percarboxylic acid and caro's acid}, volume={5,589,032}, number={1996 Dec. 31}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Chang, H. M. and Jameel, H. and Song, J. and Pan, D. and Amini, B. and Webster, J. R. and Evans, B. A.}, year={1996} }
 @misc{chang_jameel_seger_1993, title={High efficiency two-step, high-low pH chlorine dioxide pulp bleaching process}, volume={5,268,075}, number={1993 Dec. 7}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Chang, H. M. and Jameel, H. and Seger, G. E.}, year={1993} }
 @misc{chang_joyce_kirk_1987, title={Process of treating effluent from a pulp or papermaking operation}, volume={4,655,926}, number={1987 Apr. 7}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Chang, H. M. and Joyce, T. W. and Kirk, T. K.}, year={1987} }
 @misc{chang_joyce_kirk_1985, title={Process of degrading chloro-organics by white-rot fungi}, volume={4,554,075}, number={1985 Nov. 19}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Chang, H. M. and Joyce, T. W. and Kirk, T. K.}, year={1985} }
 @misc{eaton_kirk_chang_1983, title={Process for the decolorization of pulp mill bleach plant effluent}, volume={4,420,369}, number={1983 Dec. 13}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Eaton, D. C. and Kirk, T. K. and Chang, H. M.}, year={1983} }
 @misc{jividen_chang_reeves_chen_1978, title={Process for obtaining seed hull commodities including cellulosic fibers and xylitol}, volume={4,087,316}, number={1978 May 2}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Jividen, G. M. and Chang, H. M. and Reeves, R. H. and Chen, C. L.}, year={1978} }