代谢木糖和葡萄糖的重组酿酒酵母的构建

Construction of Recombinant Yeast Converting Xylose Angd Glucose to Ethanol

为使酿酒酵母(Saccharomyces cerevisiae)YS58代谢木糖产乙醇,采用PCR方法克隆得到树干毕赤酵母(Pichia stipitis)木糖醇脱氢酶基因xyl2,并将该基因和克隆得到的休哈塔假丝酵母(Candida shehatae)缺终止子的木糖还原酶基因xyt1一起连接到酵母表达载体pYES2的强启动子GAL下,得到融合表达载体pYES2-P12。通过醋酸锂转化的方法将pY- ES2-P12转入S．cerevisiae YS58中,得到S.cerevisiae YS58—12。利用所构建的重组酿酒酵母进行木糖发酵实验,结果表明该重组酵母能发酵木糖,使木糖利用率得到进一步提高,最高达到81．3％,而且能代谢木糖产生乙醇。

Candida shehatae xyll gene and Pichia stipitis xy12 gene were amplified by PCR and the xyll and xy12 were both placed under the promoter GAL of vector pYES2 to produce the recombinant expression vector pYES2P12- Subsequently the pYES2-P12 vector was transformed into S. cerevisiae YS58 by LiAc to produce the recombinant yeast YS58-12. It was indicate that the recombinant yeast YS58-12 could converse xylose to ethanol with the xylose consumption rate of 81.3%.