Biodiversity of yeast in natural fermented dairy and the traditional Kefir grain.

Biodiversity of yeast in natural fermented dairy and traditional kefir grain from Inner Mongolia was investigated. The purpose was to explore the main microflora and yeast species, laying the foundation for selecting yeast which can ferment low alcohol degree dairy. Yeast strains were isolated by gradient diluting and streaking plates, and then classified preliminarily according to colony morphology and cell morphology, followed by 5.8S rDNA-ITS restriction fragment length polymorphism (RFLP) analysis, 130 selected yeast strains were divided into 10 phenotypes and 6 molecular types. The species identified by 5.8S ITS-RFLP corresponded to Kluyveromyces marxianus, Cryptococcus sp., Saccharomyces cerevisiae, Candida tropicalis, Issatchenkia terricola and Pichia guilliermondii. Among them, K. marxianus, S. cerevisiae and P. guiltiermondii were the dominant species, which had the potential for fermenting low alcohol degree dairy. [ABSTRACT FROM AUTHOR]