Data_Sheet_1_Engineered Polyploid Yeast Strains Enable Efficient Xylose Utilization and Ethanol Production in Corn Hydrolysates.docx

The reported haploid Saccharomyces cerevisiae strain F106 can utilize xylose for ethanol production. After a series of XR and/or XDH mutations were introduced into F106, the XR-K270R mutant was found to outperform others. The corresponding haploid, diploid, and triploid strains were then constructed and their fermentation performance was compared. Strains F106-KR and the diploid produced an ethanol yield of 0.45 and 0.48 g/g total sugars, respectively, in simulated corn hydrolysates within 36 h. Using non-detoxicated corncob hydrolysate as the substrate, the ethanol yield with the triploid was approximately sevenfold than that of the diploid at 40°C. After a comprehensive evaluation of growth on corn stover hydrolysates pretreated with diluted acid or alkali and different substrate concentrations, ethanol yields of the triploid strain were consistently higher than those of the diploid using acid-pretreatment. These results demonstrate that the yeast chromosomal copy number is positively correlated with increased ethanol production under our experimental conditions.

据报道，单倍体酿酒酵母（Saccharomyces cerevisiae）菌株F106可利用木糖进行乙醇生产。将一系列木糖还原酶（XR）和/或木糖醇脱氢酶（XDH）突变引入菌株F106后，发现XR-K270R突变体的性能优于其他所有突变体。随后构建了对应的单倍体、二倍体与三倍体菌株，并对其发酵性能进行了对比分析。在模拟玉米水解液中，36小时内菌株F106-KR与二倍体菌株的乙醇得率分别可达0.45 g/g总糖与0.48 g/g总糖。以未脱毒玉米芯水解液为底物，在40℃条件下，三倍体菌株的乙醇得率约为二倍体菌株的7倍。通过对稀酸或碱预处理的玉米秸秆水解液及不同底物浓度下的菌株生长情况开展综合评估，结果显示：采用稀酸预处理时，三倍体菌株的乙醇得率始终高于二倍体菌株。上述结果表明，在本实验条件下，酵母的染色体拷贝数与乙醇产量提升呈正相关。