title: Metabolic engineering of Saccharomyces cerevisiae for increased bioconversion of lignocellulose to ethanol.
abstract: The absence of pentose-utilizing enzymes in Saccharomyces cerevisiae is an obstacle for efficiently converting lignocellulosic materials to ethanol. In the present study, the genes coding xylose reductase (XYL1) and xylitol dehydrogenase (XYL2) from Pichia stipitis were successfully engineered into S. cerevisae. As compared to the control transformant, engineering of XYL1 and XYL2 into yeasts significantly increased the microbial biomass (8.1 vs. 3.4 g/L), xylose consumption rate (0.15 vs. 0.02 g/h) and ethanol yield (6.8 vs. 3.5 g/L) after 72 h fermentation using a xylose-based medium. Interestingly, engineering of XYL1 and XYL2 into yeasts also elevated the ethanol yield from sugarcane bagasse hydrolysate (SUBH). This study not only provides an effective approach to increase the xylose utilization by yeasts, but the results also suggest that production of ethanol by this recombinant yeasts using unconventional nutrient sources, such as components in SUBH deserves further attention in the future.
authors.affiliation: Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an, 625014 Sichuan People's Republic of China ; Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, Sichuan People's Republic of China.
authors.forename: He
authors.initials: H
authors.lastname: Jun
authors.forename: Cai
authors.initials: C
authors.lastname: Jiayi
keywords: Ethanol; Saccharomyces cerevisiae; Xylitol dehydrogenase; Xylose; Xylose reductase