Identification and biodiversity of yeasts isolated from Koumiss in Xinjiang of China

Abstract:

A total of 87 yeast strains were isolated from 28 home-made koumiss samples，a traditional fermented mare milk product in Xinjiang of China. The isolates were identified by standard physiological and biochemical tests and analysis of the large-subunit (26S) rDNA gene D1/D2 domain sequences. They are proved to be Saccharomyces unisporus (48.3% of the isolates)，Kluyveromyces marxianus (27.6%) and Pichia membranaefaciens (15.0%)，Saccharomyces cerevisiae (9.2%). Among them，six isolates and a standard yeast strain were selected for analysis of D1/D2 domain sequences. They are indicated as S. unisporus，K. marxianus，S. cerevisiae，P. membranifaciens，P. fermentans，P. galeiformis and the standard yeast strain is indicated as K. lactis (100%). The results obtained demonstrate the value of using analysis of D1/D2 domain sequences methods，in conjunction with the traditional taxonomic methods based on phenotypic characteristics. This study forms an essential step towards the preservation and exploitation of the hidden oenological potential of the wealth of yeast biodiversity of the koumiss in Xinjiang Province. The result obtained shown that S. unisporus and K. marxianus were the predominant strains of koumiss in Xingjiang of China.