基于风味和产酶性能的霉菌M2的筛选及制曲工艺优化

Screening of Mold Strain M2 Based on Flavor and Enzyme-Producing Performance and Optimization of Its Daqu-Making Process

基于风味和产酶性能,从清香型白酒酒醅中分离获得1株能赋予白酒酱香风格且产糖化酶能力较高的菌株M2。通过菌体和菌落形态特征及分子生物学鉴定,确定该菌株为米根霉(Rhizopus oryzae)。以糖化酶活力为检测指标,通过单因素及响应面试验优化制曲工艺,确定菌株M2最佳制曲工艺条件为:水分含量60%,孢子接种量3×10^7~10^8cfu/mL,培养时间84h,培养温度40℃。该条件下菌株M2纯种麸曲糖化力达到最大值,为917U/g,液化力为0.72U/g,水分含量为8.34%,酸度为0.84g/L。

A mold strain M2 was isolated successfully from Qingxiang fermented grains based on the flavor and enzyme-producing properties.Through the analysis of the morphological characteristics of bacteria and colonies and molecular biological identification, it was determined as Rhizopus oryzae.Then Daqu-making process by strain M2 was optimized by single factor tests and response surface method with glucoamylase activity as the detecting indicator as follows:moisture content was 60 %,spore inoculating amount was 3×10^7 cfu/mL to 3×10^8 cfu/mL,culture time was 84 h,and culture temperature was at 35 ℃.Under the above conditions,the saccharifying power of Fuqu fermented by strain M2 reached the maximum of 917 U/g,the liquefying power was 0.72 U/g,the moisture was 8.34 %,and the acidity was 0.84 g/L.