@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_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{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} }