木薯渣中酵母菌的分离鉴定及发酵性能测定

Isolation, identification and fermentation ability of yeasts from cassava residues

为筛选出适合木薯渣发酵的专用酵母菌,试验以自然发酵的堆贮木薯渣为样品,采用传统分离培养法分离得到8株酵母菌,分别命名为Y1、Y4、Y7、Y8、Y11、Y12、Y18、Y21。通过形态学、生理生化特征鉴定及26S r DNAD1/D2区序列分析,最终鉴定出菌株Y7、Y8、Y11、Y18、Y21为皱褶假丝酵母(Candida rugosa),菌株Y1、Y4、Y12为乙醇假丝酵母(Candida ethanolica),并对其两种代表菌株Y1和Y7进行发酵性能测试,结果表明,菌株Y1和Y7的最适培养温度分别为34℃和36℃,最适pH分别为6.5和6.0,培养16 h左右,其OD600 nm值均达到最大值,分别为2.872和2.984。

In order to screen the optimal dedicated yeasts for cassava residue fermentation, using natural fermented cassava residue as raw material, eight stains were isolated by traditional culture method, namely Y1, Y4, Y7, YS, Y11, Y12, Y18, and Y21. The strains were identified by morphology, physiological and biochemical characteristics and 26S rDNA sequence analysis. The results showed that strain Y7, Y8, Y 11, Y 18, Y21 were Candida rugosa, strain Y1, Y4, Y12 were Candida ethanolica. The results of fermentation ability of representative strains showed that the optimal temperature and optimal pH of strain Y1 and Y7 was 34 ℃, 36 ℃, respectively, and 6.5, 6.0, respectively. After 16 h incubation, the OD600nm of both strains reached the maximum, which were 2.872 and 2.984, respectively.