关键词: 手工奶酪, 微生物, 多样性, Illumina MiSeq测序, COG功能预测

Abstract: This study aimed to explore the diversity of culturable lactic acid bacteria and bacteria in traditional hand-made cheese from different pastoral areas of Yili in Xinjiang. Illumina MiSeq high-throughput sequencing technology was used to sequence the V1–V3 variable region of the bacterial 16S rRNA gene. The results showed that a total of 493 bacterial genera and 780 bacterial species were found in 14 cheese samples. Ralstonia spp. and Lactobacillus spp. were the dominant bacteria and lactic acid bacteria in cheese, respectively, and Lactobacillus helveticus was the dominant Lactobacillus species. Pathogenic bacteria also existed in cheese. Furthermore, a total of 68 culturable strains suspected to be lactic acid bacteria were selected from MRS medium by the traditional culture method and identified by physiological and biochemical tests and 16S rDNA sequence homology analysis. The 68 strains turned out to belong to Lactobacillus brevis, Weissella confusa, Enterococcus faecium, Enterococcus faecalis, Enterococcus durans, Enterococcus avium, Enterococcus raffinosus, Lactobacillus plantarum, and L. helveticus. W. confusa was found to be the dominant lactic acid bacterial species in cheese. The traditional culture method allowed more accurate species-level identification of lactic acid bacteria. Prediction of gene functions showed that the microorganisms in cheese were rich in genes related to amino acid transport and metabolism. We found that although the bacterial community composition of all samples was significantly different, their functional gene composition was highly similar.

Key words: hand-made cheese, microorganism, diversity, Illumina MiSeq sequencing, COG function prediction