复合诱变选育耐高温产乙醇酵母菌的研究

为获得耐高温产乙醇菌株，对实验室保藏的菌株JZ进行分子生物学鉴定和紫外（UV）-硫酸二乙酯（DES）复合诱变，并通过单因素试验及响应面试验对筛选得到的诱变菌株进行发酵条件优化。结果表明，菌株JZ被鉴定为库德里阿兹威毕赤酵母（Pichia kudriavzevii）。经紫外（UV）-硫酸二乙酯（DES）复合诱变，得到诱变菌株JZ-2，且当紫外照射时间为80 s，硫酸二乙酯含量为5%时，在40 ℃条件下发酵6 d，乙醇产量可达4.8%vol。通过单因素试验及响应面试验确定最佳发酵条件为发酵温度40 ℃、初始pH值为4、初始糖度16 °Bx、接种量12%，静置发酵时间6 d。在此优化条件下，乙醇产量达5.6%vol，比优化前相比提高了17%。

Breeding of high temperature resistant with ethanol yield yeast by compound mutagenesis

In order to obtain the strain with high temperature resistance and ethanol yield, the strain JZ stored in laboratory was identified by molecular biology and mutated by ultraviolet (UV) -diethyl sulfate (DES), and the fermentation conditions were optimized by single factor test and response surface test. The results showed that the strain JZ was identified as Pichia kudriavzevii. The mutated strain JZ-2 was obtained by the UV and DES compound mutagenesis. Under the condition of UV irradiation time 80 s, diethyl sulfate content 5%, fermentation temperature 40 ℃, and time 6 d, the yield of ethanol could reach 4.8%vol. The results of single factor test and response surface test showed that the optimal fermentation conditions were as follows: fermentation temperature 40 ℃, initial pH 4, initial sugar content 16 °Bx, inoculum 12%, standing fermentation time 6 d. Under these optimal conditions, the ethanol yield up to 5.6%vol, which increased by 17% compared with the ethanol yield before optimization.