高产SO_2啤酒酵母菌株的选育

Breeding of a S.cerevisiae Strain with High-Yield of SO_2

对初筛的啤酒酵母进行发酵性能分析和发酵速度测定,从中选出了凝聚性强、发酵度适中、发酵速度快且SO2产量高的SY-2作为出发菌株。采用紫外辐射对SY-2菌株进行物理诱变,通过不同醋酸铅平板筛选和不同硫源培养基鉴别,得到5株产SO2含量远高于SY-2的突变菌株,其中菌株M6的SO2增长率达74%;对5株突变菌株发酵性能测定,菌株M6起发速度最快,将菌株M5、M6和SY-2发酵的成品啤酒进行感官品评,菌株M6发酵酿造啤酒的感官质量最好,表明菌株M6可作为啤酒发酵高产SO2的最佳接种菌株。

Through the analysis of the fermenting performance and the determination of the fermenting rate of beer S.cerevisiae strains after pri-mary screening, strain SY-2 with better flocculation ability, moderate fermenting degree, fast fermenting rate, and high-yield of SO2 was select-ed as the parent strain. After UV mutagenesis of strain SY-2, 5 mutant strains with high-yield of SO2 （far higher than strain SY-2） were obtained by different lead acetate plates screening and different sulfur mediums identification. Among them, SO2 yield of strain M6 increased by 74%. The analysis of the fermenting performance of those 5 mutant strains suggested that strain M6 had the fastest fermenting rate. Besides, sensory evaluation of beer fermented by strain M5, strain M6, and strain SY-2 respectively was carried out. And the results showed that beer fermented by strain M6 had the best sensory quality, which suggested that strain M6 was the most suitable strain for beer production.