高表达MAL62基因对面包酵母耐高糖的影响

Overexpression of MAL62 increased sugar tolerance of baker’s yeast

面包酵母(Saccharomyces cerevisiae)的抗逆性对于烘焙工业至关重要。以前期获得的耐冷冻酵母突变株B+MAL62为研究对象,测定其在高糖环境下的生长特性、形态特征、胞内海藻糖与甘油的积累以及产气的变化,并与市售高糖酵母进行对比。研究发现在质量分数为40%~60%的糖胁迫环境下,B+MAL62菌株的胞内海藻糖与甘油水平分别比对照菌株提升55. 03%~64. 27%与1. 2~1. 3倍,且高糖环境下B+MAL62具有更好的细胞形态稳定性,其产气速度以及最终产气量可优于市售高糖酵母。结果表明,麦芽糖酶编码基因MAL62高表达可增强面包酵母耐高糖能力。

Stress tolerance of baker’s yeast(Saccharomyces cerevisiae)is critical to the baking industry.In this study,the high sugar tolerance of cryotolerant yeast B+MAL62 obtained previously was determined and its growth characteristics,morphological stability,intracellular trehalose and glycerol content and gas production under high sugar stress were tested and compared with the commercially high-sugar tolerant yeast.Results showed that compared with the control strain,at 40%-60%sugar stress,the intracellular trehalose and glycerol levels in B+MAL62 strain were increased by 55.03%-64.27%and 1.2-1.3 times,respectively.Moreover,its morphological stability,gas production rate and final gas production in high sugar stress were better than the control strain and the commercial sugar-tolerance yeast.These results showed that overexpression of MAL62 could improve the sugar tolerance of baker's yeast.The study reveals a new way of enhancing multi-tolerance of baker’s yeast and improving the knowledge of how the maltose metabolism affects the multi-tolerance of baker’s yeast.This study provides a valuable insight into breeding of novel multi-resistant baker's yeast strains and a better understanding of other sugar metabolism,which has the potential to promote the technological level of yeast industry.