Isolation And Identification Of Latic Acid Bacteria From Traditional Dairy Products In Erdos Of Inner Mongolia And Quantitative Analysis Of Predominant Species

In this study, forty-eight samples of traditional fermented dairy products which came from local pepple were collected from three different areas of nine counties in Erdos, Inner Mongolia of China. The lactic acid bacteria (LAB) resources that were belonged to traditional fermented dairy products were isolated and identified based on pure culture method combined with 16S rRNA sequencing analysis. Meanwhile, real-time quantity PCR (qPCR) were applied to analyze numbers of dominant bacterial community in yoghurt, goat and sheep milk. This research would be more helpful in protecting the LAB resource of traditional fermented dairy products in Inner Mongolia.The viable counts of LAB in dairy products sample were determined by dilution method of plate counting. Most of them above 107 CFU/mL, only three samples were lower than 107CFU/mL, but up to 106 CFU/mL, that were ranged from 5.78 to 9.84 lg CFU/mL. LAB from these samples were isolated and identified by LAB selective medium (MRS and M17 agar) combined with phenotypic characterization method test,189 strains of LAB were preliminarily isolated.LAB were identified to species levels by 16S rRNA sequences analysis.The results showed that a total of 189 strains were classed in to 6 genus and 19 species or subspecies of LAB, including Weissella ciboria (1 strain), Weissella koreensis (1 strain), Lactobacillus brevis (1 strain), Lactobacillus helveticus (89 strains), Lactobacillus kefiranofaciens (1 strain), Lactobacillus kefiri (1 strain), Lactobacillus paracasei (2 strains) Lactobacillus plantcrrum (17 strains), Lactobacillus rhamnosus (1 strain),Enterococcus duruns (9 strains), Enterococcus faecalis (4 strains), Enterococcus faecium (2 strains),Lactococcus Lactis subsp. Lactis (31 strains) ,Leuconostoc mesenteroides (19 strains), Leuconostoc pseudotnesenteroides (6 strains), Streptococcus.thermophilus (1 strain)The predominant microflora from were Erdos of Inner Mongolia were L. helveticus (47%), Lc. lactis subsp. lactis(16%),Leu. mesenteroides(10%),L. plantarum(9%).These four accounted for 82% of the total isolation.Using qPCR research four dominant LAB belong to the number of yoghurt, goat and sheep milk in Erdos. The result was that different strains of gene copy number were ranged from 106 to 1011copise/g fece in 3 kids of fermented milk. L. helveticus、L. plantarum and Lc.Lactis.subsp. lactis quantitative relations while no distinct difference existed among yoghurt, goat and sheep milk. For Leu. mesenteroides, there have a larger difference between the three fermented milk, with the separation of the three kinds of lactic acid bacteria in fermented milk appraisal results are consistent.