Abstract:

Based on the conventional morphological and 26S rRNA gene sequencing analysis, 16 stains of Kluyveromyces
marxianus were isolated and identified from 10 samples of traditional fermented yak yogurt in the northwest of Sichuan
province. The 16 isolates had 99.3%–100% nucleotide sequence homology with that of K. marxianus available in GenBank.
Two quite different sequence types were observed in 16 isolates; one had 10 isolates, the other contained 6 isolates.
Compared with the 6 isolates, the 10 isolates had a base deletion at position 537, a point mutation G-A at position 554, and
a point mutation A-T at position 564 in the amplified fragments. In the phylogenetic tree, two different sequence types of
K. marxianus isolates fell into two distinct groups. Therefore, these results can provide useful information for understanding
the microbial composition of traditional fermented yak yogurt and genetic diversity of K. marxianus.

Key words: traditional fermented yak yoghurt, Kluyveromyces marxianus, isolation and identification, phylogenetic analysis