大曲中主要酵母菌的分子鉴定

Molecular analysis on diversity of culturable yeast isolated from Daqu

采用添加去氧胆酸钠的选择性培养基,从大曲中分离获得了7株酵母菌纯培养。以NL1和NL4为引物,对分离得到的酵母菌进行了26SrDNA D1/D2区域序列扩增、同源性比较和系统发育分析。研究结果表明:6株分离酵母菌与GenBank数据库中已知酵母有较高的相似性和相近的亲源关系,如DQY-1与Saccharomyces cerevisiae;DQY-2与Pichia deserticola;DQY-3与Zygosaccharomycesbailii;DQY-4与Debaryomyces hansenii;DQY-5与Candida pseudolambica;DQY-6与Endomyces fibuliger。另外1株酵母菌DQY-7与Uncultured fungus clone FS10有较高的相似性,而与已知酵母菌相似性较低,说明大曲中还存在一种以前尚未被认识的酵母菌。

Yeast strains were isolated from Daqu using selective culture medium added with sodium deoxycholate. 26S rDNA DI/D2 domain sequences of seven yeast strains were amplified with NLI and NL4 primers. Moreover we studied their homologous comparison and phylogenetically analysis. The results show that six yeast strains and known yeast in GenBank database have higher 26S rDNA DI/D2 domain sequence similarities and closed phylogeny, such as： DQY- 1 and Saccharomyces cerevisiae, DQY-2 and Pichia deserticola, DQY-3 and Zygosaccharomyces bailii, DQY-4 and Debaryomyces hansenii, DQY-5 and Candida pseudolambica, DQY-6 and Endomyces fibullger. Strain DQY-7 has relatively higher DNA sequence similarity to uncultured fungus clone FSI0, but lower to known ones. The results suggest that there is a kind of yeast which has never been detected in Daqu before.