西藏曲拉和云南乳饼中酵母菌的鉴定及其生物多样性

【目的】探讨西藏曲拉和云南乳饼中酵母菌的生物多样性及其分布特征,为我国传统乳制品中酵母菌资源的利用提供基础数据。【方法】从西藏和云南分别采集的5份曲拉样品和8份乳饼样品中分离出41株酵母菌,利用26SrDNAD1/D2区域序列分析对这些菌株进行了分类鉴定。【结果】曲拉和乳饼样品中酵母菌的总数分别在106-107cfu/g和102-106cfu/g之间,曲拉样品的酵母菌平均数比乳饼样品中的高34倍。共鉴定出10属12种,其中西藏曲拉的优势菌株为发酵毕赤氏酵母(Pichia fermentans)和酿酒酵母(Saccharomyces cerevisiae);云南乳饼的优势菌株为类筒假丝酵母(Candida zeylanoides)和喜仙人掌毕赤氏酵母(Pichia cactophila)。毕赤氏酵母属(Pichia)是曲拉和乳饼的共同优势属。【结论】西藏曲拉和云南乳饼中的酵母菌都具有丰富的生物多样性,但其差异性很大。

Identification and biodiversity of yeasts from Qula in Tibet and milk cake in Yunnan of China

Abstract: Objective] To analyze the biodiversity and distribution of the yeast species of Qula in Tibet and milk cake in Yunnan, and to provide essential data for the utilization of yeasts in the traditional dairy products of China. Methods] Forty-one yeast strains were isolated from 5 samples of Qula in Tibet and 8 samples of milk cake in Yunnan. The isolates were identified by the large-subunit (26S) rDNA gene D1/D2 domain sequences analysis. Results] The population of yeast in Qula varied from 106 cfu/g to 107 cfu/g. The content of yeast ranged from 102 cfu/g to 106 cfu/g in milk cake. The average population of yeast in Qula was higher than milk cake for 34 folds. These strains were grouped in 12 species belonging to 10 genera. The dominant species in Qula were Pichia fermentans and Saccharomyces cerevisiae, but Candida zeylanoides and Pichia cactophila were major population in milk cake. The results showed that Pichia was the dominant genera both in Qula and milk cake. Conclusion] There existed that yeasts of great biodiversity both of Qula in Tibet and milk cake in Yunnan, but quite different from each other.