张弓老酒大曲中耐高温酵母菌的分离鉴定及发酵条件优化

Isolation and Identification of High Temperature Yeast in Zhanggonglaojiu Daqu and Optimization of Fermentation Conditions

为筛选出耐高温的酵母菌,本实验利用传统微生物学分离培养方法,从张弓老酒中高温大曲中共初筛分离出100株酵母菌,进行复筛得到一株能在45℃下生长的酵母菌,编号为ZG-3,通过形态学特征观察并结合26S rDNA序列分析确定菌株ZG-3为库德里阿兹威毕赤酵母(Pichia kudriavzevii)。用常规方法对其耐高温和耐乙醇性以及乙醇发酵性能进行测试。研究表明菌株ZG-3的最适生长温度为37℃,最高生长温度为45℃,乙醇耐受性可达12%,在40℃条件下发酵72 h,产酒精4.7%vol。对菌株ZG-3发酵条件进行响应面优化,在最佳发酵下条件,即接种量12%、发酵温度40℃、pH为5、葡萄糖浓度140 g/L,发酵72 h,酒精度为5.2%vol。由此可见ZG-3是一株很有应用开发潜力的耐高温耐乙醇的酵母菌。

In order to screen out high-temperature-tolerant yeast,this experiment used the traditional method of microbial isolation and culture to isolate 100 strains of yeast from the initial screening of medium and high temperature daqu of Zhanggonglaojiu,and then obtained a yeast that could grow at 45℃through re-screening,numbered as ZG-3.Through morphological observation and combined with the analysis of 26 S rDNA sequence,the ZG-3 strain was identified as Pichia kudriavzevii.The high temperature resistance,ethanol resistance and ethanol fermentation performance were tested by conventional methods.The results showed that the optimum growth temperature of ZG-3 strain was 37℃,the maximum growth temperature was 45℃,and the ethanol tolerance was up to 12%.The strain was fermented at 40℃for 72 h,producing alcohol 4.7%vol.The response surface was optimized for the fermentation conditions of ZG-3 strain.Under the best fermentation conditions,the inoculation amount was 12%,the fermentation temperature was 40℃,the pH was 5,the glucose concentration was 140 g/L,the fermentation was 72 hours,and the alcohol content was 5.2%vol.It can be seen that ZG-3 is a high temperature and ethanol resistant yeast with great potential for application and development.