因玉米秸秆水解液抑制物中的糠醛和乙酸通常会抑制酿酒酵母的活力,造成乙醇产量下降。该实验为了获得抗水解抑制物并且提高乙醇产量的优良菌株,以酿酒酵母xp为出发菌株,通过常温常压等离子诱变(atmospheric and room-temperature plasma mutagenesis,ARTP)技术,得到突变体库,并以玉米秸秆水解液为筛选压力,经过25代驯化培养,筛选出优良菌株xp2。该菌体的生物量DCW最高为3.71 g/L,较原菌的3.10 g/L上升了19.68%。生长对数期为6~22 h,稳定期为22~42 h,比原菌的对数期明显提前。稳定期持续时间延长4 h,生长性能优势明显。发酵上清液中的糠醛1.43 g/L,乙酸1.21 g/L,较出发菌株发酵上清液的糠醛3.78 g/L,乙酸1.65 g/L,分别降低了62.17%和26.67%,乙醇产量和平均得率分别为38.7 g/L和0.806 g/(L·h),较出发菌株的30.3 g/L和0.631 g/(L·h),提高了17.12%和27.73%。该实验表明改造菌性状优良,转化糠醛和乙酸的能力明显提高,为今后筛选优良表型的酿酒酵母提供参考价值。
It has been known that the furfural and acetic acid in the liquid corn stalk hydrolysate could reduce yeast activity. The purpose of this study was to screen a furfural and acetic acid-resistant, high -yield ethanol Saccharomyces cerevisiae through mutation and domestication. A mutant library derived from Saccharomyces cerevisiae xp was acquired through atmospheric and room-temperature plasma (ARTP) mutagenesis. Subsequently, the mutants were grown in corn stalk hydrolysate liquid medium. After 25 generations of continuous domestication, a strain, named xp2, was obtained. This domesticated mutant had a maximum biomass DCW of 3.71 g/L, which was 19.68% higher than the wild type (3.10 g/L). It also had a short growth cycle, with 36 hours, which was 20 hours shorter than the wild type. The concentrations of the furfural and acetic acid in supernatant were 1.43 g/L and 1.21 g/L, which were 62.17% and 26.67% lower than those of the wild type (3.78 g/L and 1.65 g/L) respectively. These results indicated that the transformation capacity of the furfural and acetic acid had been significantly improved. The ethanol yield and average yield of xp2 were 38.7 g/L and 0.806 g/(L·h), which increased by 17.12% and 27.71% than that of the wild type. In conclusion, the screened strain in this study had high transformation capacity for furfural and acetic acid, and the screening method provided valuable reference for screening high performance Saccharomyces cerevisiae.
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