Isolation and Identification of Lactic Acid Bacteria and Microbial Diversity in Fresh Cow Milk from Xilin Gol

Abstract

This work was undertaken in order to study the microbial diversity in dairy products from ethnic minority habitats in Xilin Gol. Six fresh cow milk samples from Sunit Left Banner and East Ujimqin Banner (n = 3 for each region) were selected for metagenomic sequencing, and lactic acid bacteria (LAB) from these samples were isolated and identified by the traditional culture method. There results showed that a total of 165 microbial species were identified in the six milk samples, the dominant ones being Lactococcus lactis and Leuconostoc mesenteroides. Many microbial species were common to the two groups, and there was no significant difference in α- or β-diversity, but there were still significantly differential species identified between these groups. Fresh milk from Sunit Left Banner was dominated by Lactococcu phage BM13, while that from East Ujimqin Banner was dominated by Enterobacter sp. MGH8. A total of 1 408 048 genes and 412 metabolic pathways were annotated using the Uniprot database, whose functions were concentrated on amino acid metabolism and glycolic acid metabolism. A total of 47 strains were isolated from the six fresh milk samples, and L. lactis was the dominant strain, which was consistent with the metagenomic results. This study is expected to provide a theoretical basis for the safe production of fermented dairy products and the development of starter cultures.

Keywords

• xilin gol; fresh cow milk; lactic acid bacteria; metagenome; microbial diversity; separation and identification