Isolation And Identification Of Lactic Acid Bacteria And Microbial Diversity In Camel Dairy Products From Alxa Region,Inner Mongolia

Camel milk is rich in nutrients and has outstanding health functions,containing abundant resources of lactic acid bacteria.It is urgent to systematically study the microbial diversity of camel milk and complete the protection of potential probiotic lactic acid bacteria strains.This study focuses on 17 camel milk samples from the Alxa region of Inner Mongolia.The bacterial diversity in camel milk samples was analyzed using Illumina Mi Seq sequencing technology,and the lactic acid bacteria were isolated,identified,and preserved using traditional isolation and cultivation techniques.Finally,genetic analysis was conducted on the dominant bacterial species.The main research contents are as follows:(1)Analysis of bacterial diversity in camel milk.Based on Illumina Mi Seq sequencing technology,it was found that the bacteria in camel milk in the Alxa region of Inner Mongolia are mainly divided into 6 phyla,78 genera,and 157 species.There are significant differences in bacterial diversity and abundance between fresh camel milk and fermented camel milk,and the bacterial diversity of fresh camel milk is significantly higher than that of fermented camel milk.The dominant bacteria in fresh camel milk are Lactococcus lactis and Acinetobacter guilin,with relative contents of 13.22% and10.65%,respectively.The dominant strains of fermented camel milk were Lactobacillus helveticus and Lactobacillus kefiranofaciens,with relative abundance of 72.66% and8.32% respectively.(2)Analysis of metabolic pathways in camel milk.Using HUMAn N,a total of 410 metabolic pathways were annotated from camel milk,indicating significant differences in the metabolic pathways between fresh and fermented camel milk.The main metabolic pathway in fresh camel milk is amino acid metabolism,while in fermented camel milk,the main metabolic pathways are sugar metabolism and nucleotide synthesis.(3)Isolation and identification of lactic acid bacteria in camel milk.A total of 105 strains of lactic acid bacteria were isolated from 17 camel milk samples,identified as 4genera and 14 species.The dominant strain of fresh camel milk is Lactococcus lactis,accounting for 56.52% of the isolated strains of fresh camel milk;The dominant strains of fermented camel milk were Lactobacillus helveticus and Lactobacillus kefiranofaciens like,accounting for 34.15% and 22.50% of the fermented camel milk isolates,which was consistent with the results of macro genes.(4)Whole genome analysis of dominant bacterial strains.494 core gene sets and13654 pan gene sets were constructed from the published genome data of 28 dominant strains of Lactobacillus helveticus and 184 strains of NCBI,and it was found that Lactobacillus helveticus has a high potential for lysozyme and sucrose synthase.Lactobacillus helveticus showed a certain degree of regional aggregation and segregation source aggregation,with high genetic diversity.