环境胁迫对清香型白酒发酵核心微生物生长的影响

Influence of Environmental Stress on Core Microbiota of Qingxiang Baijiu

乙醇是白酒中最主要的成分,而有机酸,如乙酸、乳酸,是白酒中主要风味物质的前体。目前主要集中在对这些风味物质功能的研究上,但是却忽略了高浓度乙醇和有机酸对酒醅微生物生长的影响。本研究结果显示,不同酿酒酵母对环境胁迫的耐受性差异不大,大部分菌株可以耐受0.5%乙酸、4%乳酸和20%乙醇;不同产酸菌对环境胁迫的耐受性差异较大,大部分菌株可以在含有0.5%乙酸和12%乙醇的培养基上生长,有6株菌可以在1%乳酸培养基上生长。因此,酒醅中的乙醇和有机酸并不会影响核心微生物的生长,而导致酿酒过程中后期酒精产量停滞的原因和机制尚待进一步研究。

Ethanol is the main component in Baijiu,while organic acids,such as acetic acid and lactic acid,are the key precursors of flavor components in Baijiu.Recent researches mainly focused on the functions of these flavor components,and neglected the impact of high-concentration ethanol and organic acids on the growth of microorganisms in the fermented grains.Our study demonstrated that,most Saccharomyces cerevisiae strains were resistant to 0.5%acetic acid,4%lactic acid or 20%ethanol;most acid-producing strains were able to grow on the medium with 0.5%acetic acid or 12%ethanol,while 6 strains were resistant to 1%lactic acid.These data indicates that the ethanol and organic acids in the fermented grains would not inhibit the growth of the core microbiota,and the mechanism of the suppression of ethanol biosynthesis in the middle and late stage of fermentation needs further investigation.