白酒酿造酒醅与周边土壤中酵母菌多样性及东方伊萨酵母发酵特性比较

采用平板分离法，从白云边酒厂酒醅和周边土壤中分离获得120株酵母菌，采用26S rDNA D1/D2序列分析，比较2种环境中酵母菌的多样性，并测定不同来源的东方伊萨酵母（Issatchenkia orientalis）菌株耐酸、耐温和乙醇耐受性及发酵产物乙醇和乙酸乙酯含量差异。结果表明，来自酒醅和土壤中的酵母菌多样性差异较大，土壤、酒醅中热带假丝酵母（Candida tropicalis）、盔形毕赤酵母（Pichia manshurica）分别占优势。I. orientalis在土壤和酒醅中均比较丰富，其耐酸、耐高温和高温下耐乙醇能力有差异，且来源酒醅的菌株在耐受性方面较来源土壤菌株有一定优势，来源酒醅I. orientalis菌株发酵产乙醇和乙酸乙酯含量显著高于来源土壤菌株。该研究结果将有助于揭示参入白酒发酵的菌种来源和I. orientalis优良菌株的选育。

Comparison of diversity of yeast and fermentation characteristic of Issatchenkia orientalis from fermented grains and surrounding soil of Baijiu production

120 strains of yeast were isolated from the fermented grains and the surrounding soil of Baiyunbian distillery by plate separation method. The yeast diversity in the two environments was compared by 26S rDNA D1/D2 region sequence analysis, and the acid, temperature and ethanol tolerance of the different sources of Issatchenkia orientalis strains and the differences of ethanol and ethyl acetate contents in fermentation products were determined. The results showed that there were great differences in yeast diversity between the soil and the fermented grains, and their dominant yeasts were Candida tropicalis and Pichia manshurica, respectively. The I. orientalis were abundant in the soil and fermented grains. The acid tolerance, high temperature tolerance and ethanol production ability of the different sources of I. orientalis strains were different, the strains from fermented grains had certain advantages in tolerance compared with the strains from soil, and the content of ethanol and ethyl acetate produced by the I. orientalis strains from fermented grains was significantly higher than that of the I. orientalis strains from soil. The research results could help to reveal the source of strains involved in Baijiu fermentation and the breeding of superior strains of I. orientalis.