酿酒酵母耐受玉米秸秆水解液抑制物基因的功能鉴定

Energy production from biomass has been attracting great attention in recently years. Biomass pretreatment normaly generates numerous inhibitors, which can greatly slow down ethanol fermentation. Therefore, it is crucial to characterize inhibitor tolerance related genes in Saccharomyces cerevisiae and unravel their mechanisms. From a previously constructed xylose-fermenting strain CIBTS0735, the applicant obtained an inhibitor tolerance enhanced strain CIBTS0735EI by permanantly adapting CIBTS0735 to the corn stover hydrolysate obtained from COFCO. CIBTS0735EI consumed 82% of total xylose, compared to 12% of CIBTS0735. This project aims to uncover several (mutant) genes that can enhance inhibitor tolerance by generating and screening the genome library of CIBTS0735EI. Subsequently, tolerance mechanisms would be uncovered by analyzing genes’ functions. The results of this project can not only deep our understanding of inhibitor tolerance in Saccharomyces cerevisiae but also direct the development of inhibitor tolerant strains. This can further speed up the commercilization of cellulosic ethanol in China and worldwide.

秸秆类资源的能源化利用是当前的研究热点。预处理时产生的多种抑制物会大幅延缓水解液的乙醇发酵，致使纤维素乙醇难以商业化。因此，鉴定酿酒酵母的抑制物耐受基因以及揭示相应耐受机理具有重要意义。申请人以前期构建的木糖发酵酿酒酵母CIBTS0735为出发菌株，通过在玉米秸秆水解液（中粮肇东纤维素乙醇中试料液）中进行长期的传代培养，获得了抑制物耐受能力大幅增强的驯化菌株CIBTS0735EI，其木糖利用率从12%上升到了82%。本课题拟以驯化菌株CIBTS0735EI为研究对象，通过构建和筛选基因组表达文库，鉴定水解液驯化过程中获得的增强抑制物耐受能力的突变基因；进而通过突变基因功能分析，揭示抑制物耐受机理。研究成果不仅能加深我们对酿酒酵母抑制物耐受的理解，也能反过来指导抑制物耐受菌种的开发，进而加快国内乃至全球纤维素乙醇的商业化进程。