Investigation Of Bacterial Diversity In Traditional Fermented Dairy Products From Xilingol Of Inner Mongolia And Bayankhongor Of Mongolia

In this study,traditional pure culture method was performed to obtain lactic acid bacteria resources in 12 samples of koumiss from Xilingol of Inner Mongolia and 16 samples of traditional fermented dairy products from Bayankhongor of Mongolia,including 4 samples of koumiss,3 samples of fermented cow milk and 9 samples of cheese.PacBio single-molecule real-time sequencing(PacBio SMRT)technology was used to investigate the bacterial composition of traditional fermented dairy products;meanwhile,compare analysis was performed to analyze the bacterial microbiota structure of koumiss samples in different regions from Inner Mongolia and Mongolia.One hundred and five lactic acid bacteria(LAB)isolates were isolated from traditional fermented dairy products,which were identified as belonging to 2 genera and 8 species or subspecies.Among this,Lactobacillus helveticus and Lactobacillus kefiranofaciens was the predominant species with the proportion of 79.05%.LAB communities in traditional fermented dairy products varied with types of dairy foods.Through PacBio SMRT,bacteria in 12 samples of koumiss from Xilingol of Inner Mongolia identified as 60 bacterial species in 34 genera and 5 phyla.Among this,Streptococcus paranberis(62.82%)and Lactobacillus helveticus(27.12%)was the most abundant species.The results showed that bacterial diversity and relative abundance varied between koumiss samples.Through SMRT,bacteria in samples of fermented cow milk,koumiss and cheese from Bayankhongor of Mongolia identified as 234 bacterial species in 155 genera and 11 phyla.Lactobacillus helveticus,Lactobacillus delbrueckii and Enterobacter xicingfangensis was the most abundant species in koumiss,fermented cow milk and cheese,respectively.Principal coordinate analysis(PCoA)based on UniFrac distance showed that traditional fermented milk samples of the same type and different types had obvious aggregation tendency and separation state,respectively.The results revealed that microbial community structure and relative abundance varied with types of traditional dairy products.By performing compare analysis with sequences of koumiss samples in different regions.It showed that bacterial community structure had certain similarity and differences.Firmicutes was the predominant phyla in all koumiss samples,Lactobacillus was the predominant genera in koumiss groups of MBK and MG from Mongolia,while Streptococcus was the predominant genera in koumiss groups of IM from Inner Mongolia.Meanwhile,there were 137 common OTUs between three sample groups of koumiss,which 103 OTUs of the common OTUs in sample group of MBK,MG and IM was identified as Lactobacillus helveticus.PCoA and cluster analysis showed the bacterial community composition had a clear tendency to aggregate and separate within and between sample groups,respectively.SMRT sequencing technology combined with pure culture methods revealed that the traditional fermented dairy products iin Inner Mongolia and Mongolia were rich in bacteria and complex in structure.That provides valuable resources for LAB resources development and microbial diversity research of dairy products.