spt15突变基因对酿酒酵母木糖利用的影响

Effects of mutational spt15 gene to xylose utilization of Saccharomyces cerevisiae

摘要:

利用基因工程手段得到重组菌YPH499-3中的spt15有效突变基因, 通过表达载体 pYX212转化入酿酒酵母原始菌株YPH499中, 重新获得酿酒酵母重组菌株。对其性状进行研究, 结果表明该菌株能有效利用木糖并共发酵木糖和葡萄糖。在30oC、200 r/min, 发酵72 h时, 50 g/L木糖的利用率为82.0%, 乙醇产率为28.4%; 当木糖和葡萄糖以质量比1:1混合发酵时, 木糖和葡萄糖的利用率分别为80.4%和100%, 乙醇产率为31.4%; 同时发现木糖醇的含量极低。从而验证了有效突变基因spt15-10对酿酒酵母共发酵木糖和葡萄糖产酒精的影响。

Abstract:

We used genetic methods to get a mutational spt15 gene from the recombinant strain Saccharomyces cerevisiae YPH499-3, screened by global transcription machinery engineering (gTME) approach. We transformed the gene into the original strain Saccharomyces cerevisiae YPH499 using the vector pYX212, then got a new recombinant strain. We studied the characteristic of this strain and found that it could metabolize xylose and co-ferment xylose and glucose. Under the fermentation condition of 30oC, 200 r/min, 72 h , the utilization ratio of xylose was 82.0%, with 32.4% of ethanol yield when the carbon source in the media was 50 g/L xylose, while the utilization ratio of xylose and glucose was 80.4% and 100% respectively, with the 31.4% of ethanol yield when the carbon source was 50 g/L glucose/xylose (1:1). Meanwhile, the concentration of the by-product xylitol was very low. This study demonstrates the effect which the forward mutation of spt15 gene makes to the co-fermentation of xylose and glucose to ethanol by Saccharomyces cerevisiae.