为了提高啤酒酵母对发酵环境中存在的多种压力的耐受性,采用紫外线对啤酒工业生产菌株Y-1进行诱变。经过米卡芬净平板的初筛和压力平板的复筛,获得了2株压力耐受性明显增强的啤酒酵母MR0-8和MR1-2。与出发菌株Y-1相比,突变菌株MR0-8和MR1-2发酵结束细胞活力分别提高了19%和34%。进一步对出发菌株Y-1和突变菌株MR1-2的压力耐受途径的基因进行了RT-PCR分析。结果显示:在正常条件下,MR1-2的压力应答基因及细胞完整性基因的表达量比出发菌株Y-1都有不同程度的提高;在乙醇压力和高渗透压压力下,菌株Y-1的大部分相关基因都上调,而MR1-2的相关基因则表现出复杂的应答反应。

In order to improve resistance to various stresses during fermentation of brewing yeast,UV mutagenesis was carried out on industry brewing yeast Y-1. Strain MR0-8 and MR1-2 with obviously improved stress tolerance were isolated on micafungin plate and stressful plates. Compared with the origin strain Y-1,the viability of strain MR0-8 and MR1-2 at the end of fermentation were improved by 19% and 34%,respectively. Further RT-PCR analysis indicated that the expression of genes for stress response and genes in cell wall integrity pathway were higher in MR1-2 than those in Y-1. In response to ethanol and hyperosmolarity stress,most responsive genes were unregulated in Y-1,while the performance of these genes was more complicated in MR1-2.