西藏传统发酵牦牛酸奶中乳酒假丝酵母的分离鉴定与系统发育学分析

目的开发西藏传统发酵牦牛酸奶的微生物种质资源。方法对拉萨周边牧场的10份传统发酵牦牛酸奶样品进行乳酸菌的分离过程中得到6株酵母菌,通过常规形态特征、生化和基质解吸电离飞行时间质谱法(matrix desorption ionization time-of-flight mass spectrometry, MALDI-TOF-MS)进行鉴定,对其质谱标识峰进行蛋白质水平同源性分析,采用ITS序列对其进行基因学比对。结果经生化和质谱鉴定分离的6株酵母为乳酒假丝酵母,分离酵母和已知乳酒假丝酵母通过ITS序列在GENEBANK比结果为命名有差异为马克斯克鲁维酵母,但乳酒假丝酵母可认定为其无性型变种。蛋白质同源分析结果表明6株分离菌与已知乳酒假丝酵母在蛋白质水平有一定差异,收集到其特征性蛋白质片段的标识峰12组。结论乳酒假丝酵母的分离与研究为西藏传统发酵牦牛酸奶中酵母菌的开发提供理论支撑。

Isolation, Identification and Phylogenetic Analysis of Candida kefyr in Traditional Fermented Yak Yoghurt in Tibet

Six strains of yeast were obtained from the Lactobacillus sp. isolation of 10 traditional fermented calf yoghurt samples from the pastures around Lhasa, which were identified as Candida kefyr by conventional morphological, biochemical and matrix desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) methods. Homology analysis at protein level was performed on the mass spectrometric peaks of the Candida kefyr, and the results showed that there were differences in protein between the six isolates and the known standard strains, because the former had 12 Characteristic peaks, which were characteristic protein fragments. The six isolates were identified as Kluyveromyces marxianusby the ITS sequence comparison in the GENEBANK , and Candida kefyr,is its teleomorph. The experimental results provide theoretical support for the development of yeast in traditional fermented yogurt in Tibet.