一株高产乙酸乙酯酵母的鉴定及产酯条件的研究

以不同酒曲中筛选出的一株产乙酸乙酯能力较强的酵母Y2为研究对象，利用磷脂脂肪酸分析和分子生物学方法对其进行鉴定，通过单因素试验分别考察培养方式、发酵时间、发酵温度和糖化液糖度4个因素对酵母Y2产酯能力的影响，采用正交试验和验证试验对酵母Y2的产酯条件进行优化。结果表明，酵母Y2为异常毕赤酵母（Pichia anomala），其脂肪酸成分以18∶1ω9c为主；发酵温度和发酵时间对酵母菌株Y2产酯量具有显著性影响（P＜0.05），优化后的产酯条件为：发酵温度28 ℃，高粱糖化液糖度12 °Bx，静置培养5 d；在此最优条件下，酵母Y2产乙酸乙酯的量可达到3.47 g/L。

Identification and ester-producing conditions of a high ethyl acetate-producing yeast

Using a high ethyl acetate-producing yeast strain Y2 screened from different Jiuqu as research object, the yeast Y2 was identified by phospholipid fatty acid analysis and molecular biology methods. The effects of culture mode, fermentation time, fermentation temperature, and saccharification liquid sugar content on ester-producing ability of yeast Y2 were investigated by single factor experiment. The ester-producing conditions of yeast Y2 were optimized by orthogonal experiments and verification experiments. Results indicated that yeast Y2 was Pichia anomala, the main fatty acid composition was 18∶1ω9c, fermentation temperature and time had significant effect on ester yield of yeast Y2 (P＜0.05). The optimum ester-producing conditions were as follows: fermentation temperature 28 ℃, sugar content of sorghum saccharification liquid 12 °Bx, static culture for 5 d, in the optimum conditions, the ethyl acetate yield of yeast Y2 could reach 3.47 g/L.