@article{sun_cheng_himmel_skory_adney_thomas_tisserat_nishimura_yamamoto_2007, title={Expression and characterization of Acidothermus cellulolyticus E1 endoglucanase in transgenic duckweed Lemna minor 8627}, volume={98}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2006.09.055}, abstractNote={Endoglucanase E1 from Acidothermus cellulolyticus was expressed cytosolically under control of the cauliflower mosaic virus 35S promoter in transgenic duckweed, Lemna minor 8627 without any obvious observable phenotypic effects on morphology or rate of growth. The recombinant enzyme co-migrated with the purified catalytic domain fraction of the native E1 protein on western blot analysis, revealing that the cellulose-binding domain was cleaved near or in the linker region. The duckweed-expressed enzyme was biologically active and the expression level was up to 0.24% of total soluble protein. The endoglucanase activity with carboxymethylcellulose averaged 0.2 units mg protein−1 extracted from fresh duckweed. The optimal temperature and pH for E1 enzyme activity were about 80 °C and pH 5, respectively. While extraction with HEPES (N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulfonic acid]) buffer (pH 8) resulted in the highest recovery of total soluble proteins and E1 enzyme, extraction with citrate buffer (pH 4.8) at 65 °C enriched relative amounts of E1 enzyme in the extract. This study demonstrates that duckweed may offer new options for the expression of cellulolytic enzymes in transgenic plants.}, number={15}, journal={BIORESOURCE TECHNOLOGY}, author={Sun, Ye and Cheng, Jay J. and Himmel, Michael E. and Skory, Christopher D. and Adney, William S. and Thomas, Steven R. and Tisserat, Brent and Nishimura, Yufuko and Yamamoto, Yuri T.}, year={2007}, month={Nov}, pages={2866–2872} }
 @article{sun_cheng_2005, title={Dilute acid pretreatment of rye straw and bermudagrass for ethanol production}, volume={96}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2004.12.022}, abstractNote={Ethanol production from lignocellulosic materials provides an alternative energy production system. Rye and bermudagrass that are used in hog farms for nutrient uptake from swine wastewater have the potential for fuel ethanol production because they have a relative high cellulose and hemicellulose content. Dilute sulfuric acid pretreatment of rye straw and bermudagrass before enzymatic hydrolysis of cellulose was investigated in this study. The biomass at a solid loading rate of 10% was pretreated at 121 degrees C with different sulfuric acid concentrations (0.6, 0.9, 1.2 and 1.5%, w/w) and residence times (30, 60, and 90 min). Total reducing sugars, arabinose, galactose, glucose, and xylose in the prehydrolyzate were analyzed. In addition, the solid residues were hydrolyzed by cellulases to investigate the enzymatic digestibility. With the increasing acid concentration and residence time, the amount of arabinose and galactose in the filtrates increased. The glucose concentration in the prehydrolyzate of rye straw was not significantly influenced by the sulfuric acid concentration and residence time, but it increased in the prehydrolyzate of bermudagrass with the increase of pretreatment severity. The xylose concentration in the filtrates increased with the increase of sulfuric acid concentration and residence time. Most of the arabinan, galactan and xylan in the biomass were hydrolyzed during the acid pretreatment. Cellulose remaining in the pretreated feedstock was highly digestible by cellulases from Trichoderma reesei.}, number={14}, journal={BIORESOURCE TECHNOLOGY}, author={Sun, Y and Cheng, JJ}, year={2005}, month={Sep}, pages={1599–1606} }
 @article{sun_muthukumarappan_2002, title={Changes in functionality of soy-based extrudates during single-screw extrusion processing}, volume={5}, ISSN={["1094-2912"]}, DOI={10.1081/JFP-120005793}, abstractNote={The effects of defatted soy flour content, feed moisture, screw speed and temperature on the functionality of soy-based extrudates were studied. Defatted soy flour and corn flour were mixed with ratios from 10% up to 30% of soy flour. The moisture contents of the blends (wet basis) have three levels: 15%, 18% and 21%. The barrel temperatures and screw speeds of the single screw extruder were controlled from 155 to 185°C and 180 to 220 rpm range, respectively. Shear force, color of the extrudates, expansion ratio, bulk density and water absorption were measured. Higher soybean flour content significantly increased shear force, bulk density and Hunter a* values and significantly decreased expansion ratio and Hunter L* values. High feed moisture significantly increased bulk density and Hunter L* values while significantly decreasing shear force and Hunter a* values. High process temperature significantly increased shear force and Hunter a* values and decreased bulk density. Increasing screw speed resulted in significantly increased bulk density. Understanding the relationship between extrusion parameters and physicochemical properties of the extrudates provides a basis for effective product development.}, number={2}, journal={INTERNATIONAL JOURNAL OF FOOD PROPERTIES}, author={Sun, Y and Muthukumarappan, K}, year={2002}, pages={379–389} }
 @misc{sun_cheng_2002, title={Hydrolysis of lignocellulosic materials for ethanol production: a review}, volume={83}, ISSN={["1873-2976"]}, DOI={10.1016/S0960-8524(01)00212-7}, abstractNote={Lignocellulosic biomass can be utilized to produce ethanol, a promising alternative energy source for the limited crude oil. There are mainly two processes involved in the conversion: hydrolysis of cellulose in the lignocellulosic biomass to produce reducing sugars, and fermentation of the sugars to ethanol. The cost of ethanol production from lignocellulosic materials is relatively high based on current technologies, and the main challenges are the low yield and high cost of the hydrolysis process. Considerable research efforts have been made to improve the hydrolysis of lignocellulosic materials. Pretreatment of lignocellulosic materials to remove lignin and hemicellulose can significantly enhance the hydrolysis of cellulose. Optimization of the cellulase enzymes and the enzyme loading can also improve the hydrolysis. Simultaneous saccharification and fermentation effectively removes glucose, which is an inhibitor to cellulase activity, thus increasing the yield and rate of cellulose hydrolysis.}, number={1}, journal={BIORESOURCE TECHNOLOGY}, author={Sun, Y and Cheng, JY}, year={2002}, month={May}, pages={1–11} }