高产乙酸乙酯酵母菌株的筛选

为得到具有高产乙酸乙酯特性的酵母菌株,对实验室保存及酒醅中分离的酵母菌株,依次进行平板初筛、麦芽汁闻香、高粱汁发酵筛选。获得具有高产乙酸乙酯特性的酵母菌株8株,分别是MY0-3、MY5-9、B003、C3、B005、Y1、P6和74,MY0-3菌发酵产乙酸乙酯量达3.73 g/L。MY0-3为异常毕赤酵母,具有较低的酒精耐受性8%vol、温度耐受性35℃,最高耐受酸度3.0。通过正交试验优化得到最佳发酵产酯条件为p H3.5、酒精度2%vol、温度25℃、发酵时间9 d,其乙酸乙酯的产量为6.2 g/L。MY0-3固态小试中乙酸乙酯含量提高了19.5%。

Screening of Yeast Strains with High-Yield of Ethyl Acetate

In order to obtain yeast strains with high-yield of ethyl acetate, the yeast strains preserved in the laboratory and isolated from fermented grains were successively screened by plate preliminary screening, malt juice odor and sorghum juice fermentation screening. Eight strains with high-yield of ethyl acetate were obtained including MY0-3, MY5-9, B003, C3, B005, Y1, P6 and 74.The yield of ethyl acetate of MY0-3 reached up to 3.73 g/L. MY0-3 is Pichia anomala and has low alcohol tolerance of 8 %vol, temperature tolerance of 35 ℃, and high acidity tolerance of 3.0. Its best fermentation conditions were summed up through orthogonal experiments as follows: pH was 3.5, alcohol content was 2 %vol, fermentation temperature at 25 ℃, and fermentation time was 9 d. As a result, the yield of ethyl acetate was 6.2 g/L. In the trial solid-state fermentation of MY0-3, the content of ethyl acetate got increased by 19.5 %.