title: Enhanced Bioconversion of Cellobiose by Industrial Saccharomyces cerevisiae Used for Cellulose Utilization.
abstract: Cellobiose accumulation and the compromised temperature for yeast fermentation are the main limiting factors of enzymatic hydrolysis process during simultaneous saccharification and fermentation (SSF). In this study, genes encoding cellobiose transporter and β-glucosidase were introduced into an industrial Saccharomyces cerevisiae strain, and evolution engineering was carried out to improve the cellobiose utilization of the engineered yeast strain. The evolved strain exhibited significantly higher cellobiose consumption rate (2.8-fold) and ethanol productivity (4.9-fold) compared with its parent strain. Besides, the evolved strain showed a high cellobiose consumption rate of 3.67 g/L/h at 34°C and 3.04 g/L/h at 38°C. Moreover, little cellobiose was accumulated during SSF of Avicel using the evolved strain at 38°C, and the ethanol yield from Avicel increased by 23% from 0.34 to 0.42 g ethanol/g cellulose. Overexpression of the genes encoding cellobiose transporter and β-glucosidase accelerated cellobiose utilization, and the improvement depended on the strain background. The results proved that fast cellobiose utilization enhanced ethanol production by reducing cellobiose accumulation during SSF at high temperature.
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Meng-Long
authors.initials: ML
authors.lastname: Hu
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zha
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Lin-Wei
authors.initials: LW
authors.lastname: He
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Ya-Jin
authors.initials: YJ
authors.lastname: Lv
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Ming-Hua
authors.initials: MH
authors.lastname: Shen
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science and Technology Tianjin, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Bing-Zhi
authors.initials: BZ
authors.lastname: Li
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin UniversityTianjin, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin UniversityTianjin, China.
authors.forename: Ying-Jin
authors.initials: YJ
authors.lastname: Yuan
keywords: cellobiose utilization; evolution engineering; industrial strain; simultaneous saccharification and fermentation; synthetic biology