Construction of mixed-sugar fermenting recombinant Saccharomyces cerevisiae and ethanol production from Jerusalem artichoke stalk by simultaneous saccharification and fermentation
1. School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning 116024, China; 2. School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China 在期刊界中查找 在百度中查找 在本站中查找
[Objective] This study aimed to construct highly efficient recombinant Saccharomyces cerevisiae strain for cellulosic bioethanol production from Jerusalem artichoke stalk (JAS). [Methods] S. cerevisiae strain YB-2625 was selected as a host strain to construct xylose co-fermenting strain YB-2625 CCX, after which multicopies of xylitol dehydrogenase (XDH) encoding gene were integrated into the rDNA locus of YB-2625 CCX, and the most efficient strain named YB-73 was obtained. Finally, ethanol production from JAS was investigated by simultaneous saccharification and fermentation (SSF) using YB-73. [Results] YB-73 showed improved ethanol production by 13.9% compared with that of YB-2625 CCX and the xylitol yield of YB-73 was reduced to 0.31 g/g xylose from 0.89 g/g xylose by YB-2625 CCX when fermenting with 90 g/L glucose and 30 g/L xylose. Meanwhile, flocculation of YB-73 was observed in the presence of xylose, and the strain also showed high tolerance towards 5 g/L acetic acid and high temperature. The highest ethanol titer of 6.10% (v/v) was achieved from JAS in the process of SSF using YB-73. [Conclusion] Combination of host selection, introduction of xylose-consuming pathway and multi-copy overexpression of XDH in rDNA locus is a rational strategy to improve cellulosic bioethanol production performance of S. cerevisiae using JAS. This is the first report using recombinant S. cerevisiae to produce cellulosic ethanol from JAS.
