四川麸醋曲药中酵母菌的分离鉴定及发酵特性

Isolation,Identification and Fermentation Characteristics of Yeast from Sichuan Bran Vinegar Starter

通过平皿生化反应从四川麸醋曲药中分离出产酯能力较强的酵母菌,利用18S rDNA同源序列分析对其进行鉴定,研究其最适生长pH值、酒精耐受性、碳源和氮源同化能力,并利用顶空固相微萃取-气质联用技术对其代谢产物进行研究。结果表明:产酯透明圈实验分离出的产酯能力较强的酵母菌为异常威克汉姆酵母菌亚种(Wicherhamomyces sp. Lzcq 2014)。该株酵母菌的最适合生长pH值为5. 0～5. 5,在酒精度为10%的情况下几乎不生长;对不同碳源同化能力强弱顺序依次是葡萄糖、蔗糖、麦芽糖、乳糖、淀粉;对不同氮源同化能力强弱顺序依次是酵母膏、蛋白胨、硫酸铵、尿素。该酵母菌代谢产物主要成分为乙酸乙酯,其质量浓度为0. 640 79 mg/L,且乙酸乙酯浓度远高于其他代谢产物。其他代谢产物分别为甲酸异戊酯、丙酸苯乙酯、苯乙醇,质量浓度分别为0. 041 36、0. 039 43、0. 023 00 mg/L。

The yeast with strong ability producing ester was isolated by biochemical reactions in plate from Sichuan bran vinegar starter and identified by 18S rDNA homology analysis. The growth characteristics such as optimal growth pH, alcohol tolerance, assimilation capacity to carbon sources, and nitrogen sources were studied. And metabolites were studied by solid phase microextraction plus GC-MS techniques. The result showed that the yeast isolated from ester transparent ring experiment was Wicherhamomyces sp. Lzcq 2014. The optimal growth pH was about 5.0 to 5.5, and it didn t grow when the alcohol content was 10%. Meanwhile, the ability assimilating carbon source in desending order was glucose, sucrose, maltose, lactose, and starch, and the ability assimilating nitrogen source was yeast extract, peptone, ammonium sulfate, and urea. The main metabolite was ethyl acetate, and the concentration reached 0.640 79 mg/L. The contents of isoamyl formate, propanoic acid, and phenylethyl alcohol, were 0.041 36, 0.039 43, 0.023 00 mg/L, respectively.