小曲中优质产酯酵母分离鉴定及其产酯条件优化

Isolation and identification of efficient ester-producing yeast in Xiaoqu and optimization of ester production conditions

从酿酒小曲中分离获得优质产酯菌株Y5,经产酯培养基初筛其总酯2.684 g/L,乙酸乙酯含量为2.481g/L。经生理生化实验和分子鉴定,确定Y5菌株为异常威克汉姆酵母(Wickerhamomyces anomalus)。通过采用单因素和四因素四水平正交实验对该菌产酯条件进行优化,试验结果表明在初始p H 4、乙醇体积分数4%的培养基中30℃恒温发酵3d为最适产酯条件,其Y5菌株总酯产量为4.065 g/L,乙酸乙酯产量3.677 g/L。相比优化之前,其总酯含量显著提高51.5%,乙酸乙酯含量显著提高48.2%。

An efficient ester-producing yeast(numbered as Y5) was isolated from three kinds of Xiaoqu and identified as Wickerhamomyces anomalus by physiological biochemical tests and molecular biology method. Using esterproducing culture-medium,2. 481 g/L of ethyl acetate among 2. 684 g/L of total ester was obtained. Using orthogonal experiments to optimize ester-production conditions,results showed that the appropriate culture conditions for this yeast was fermentation in alcohol 4%,pH 4,at 30 ℃ for 3 d. Under this condition,total ester and ethyl acetate was 4. 065 g/L and 3. 677 g/L respectively,which was significantly increased about 51. 5% and 48. 2% respectively compared that before optimization. The strain has strong ability to produce ester and there is a bright prospect for its application in industry.