Isolation And Identification Of Lactic Acid Bacteria And Bacterial Diversity Of Traditional Cheese In Kazakhstan

In this study, six samples of traditional cheese which came from local people were collected from two different areas of Kazakhstan. The lactic acid bacteria(LAB) that were belonged to traditional cheese of cow milk products were isolated, identified and stored based on traditional pure culture method combined with 16S rDNA sequencing analysis. Meanwhile, the bacterial biodiversity of samples were analyzed by single molecule real time (SMRT) sequencing. The conclusions were showed as follows:(1) The viable counts of LAB in cheese products were determined by dilution method of plate counting, besides the results of 4 samples were ranged from 8.50×102～8.80×105 CFU/g, the other 2 samples were lower than 10 CFU/g. LAB from these samples were isolated and purified by LAB selective medium (MRS and M17) combined with morphological observation, gram faerbung and catalase test,33 strains of LAB isolates were preliminarily isolated.(2) Thirty-three isolates were identified to species levels by 16S rDNA sequences analysis. The results showed that all the isolates were classified into four genera,and eight species, Lactobacillus were the dominating genera by 69.70%(23 strains) of total, and the dominating species was Lactobacillus helveticus by 27.23%(9 strains); 8 strains of Lactobacillus delbrueckii(24.24%),8 strains of Streptococcus thermophiles (24.24%),3 strains of Lactobacillus brevis (9.09%),2 strains of Lactobacillus plantarum (6.06%),1 strains of Enterococcus faecium (3.03%),1 strains of Lactobacillus crustorum (3.03%),1 strains of Pediococcus pentosaceus (3.03%).(3) Bacterial diversity in six traditional cheese samples collected from Kazakhstan were comprehensively examined by single molecule real time sequencing. The results showed that an abundant and complex microflora was presented in traditional cheese samples. One hundred and forty four species and/or subspecies and ninty four genera species belonging to fourteen phyla were identified after RDP Ⅱ database and GREENGENS sequencing analysis. The dominating phyla was Firmicutes by 92.46%, and Lactobacillus was the dominating genera species by 42.12%. Lactococcus lactis (28.93%) and Lactobacillus helveticus (26.43%) could be recognised as the dominating LAB species in these samples.