缺失PHO13基因与进化工程构建高效利用木糖酵母

过表达了木糖还原酶、木糖醇脱氢酶和木酮糖激酶基因的重组工业酿酒酵母菌株KAM-6X内缺失了编码对硝基苯磷酸盐磷酸化酶的PHO13基因,接着通过EMS诱变和进化工程筛选,获得了一株高效利用木糖的菌株,命名为PE。有氧条件下,在含50 g/L木糖和100 g/L木糖的YPX中最大比生长速率分别为0.299和0.282 h^-1,分别比出发菌提高了95.43%和102.87%,同时PE菌株能在前24 h内耗掉36.12 g/L木糖,48 h内耗掉70.25 g/L木糖。微好氧条件下副产物产量降低,糖醇转化率最高达到0.382 g/g,证明PE是一株高效利用木糖发酵的工业酵母菌株。

Construction of An Efficient Xylose-Utilizing Saccharomyces cerevisiae Strain by Deletion of PHO13 Gene and Evolutionary Engineering

Xylose is the second most abundant sugar and the most prevalent pentose sugar found in lignocelluloses. To improve xylose utilization, significant efforts have focused on the metabolic engineering of Saccharomyces cerevisiae. In this study, efficient xylose-utilizing Saccharomyces cerevisiae strain PE, was constructed by deletion of PHO13 gene encoding para-nitrophenyl phosphatase and subjected to EMS mutagenesis followed by evolution engineering in an industrial recombinant strain, KAM-6X, which over expressed the genes encoding xylose reductase, xylitol dehydrogenase and xylulokinase. Under aerobic condition, the specific growth rate of PE was 0.299 h^-1 and 0.282 h^-1 in YPX containing 50 g/L and 100 g/L xylose, which improved about 95.43% and 102.87%, respectively. And PE strain can consume 36.12 g/L xylose in 24 h and 70.25 g/L xylose in 48 h. Under oxygen-limited condition, ethanol yield reached 0.382 g/g with less glycerol production and high acetate level. It proves that PE is an efficient xlose-fermenting industrial yeast strain.