Isolation And Identification Of Latic Acid Bacteria From Traditional Dairy Products In Baotou And Bayannur Of Inner Mongolia And Quantitative Analysis Of Predominant Species By Q-PCR

Traditional dairy products were the natural habitats of lactic acid bacteria. In order to reveal the population structure of lactic acid bacteria, and preserve lactic acid bacteria from traditional dairy products in arid and desert areas. Lactic acid bacteria were isolated and identified using pure culture method and 16S rRNA gene sequencing from sixty nine samples of traditional dairy products, including yogurt, cream, cheese and milk, which were collected from northern of Baotou and pastoral of Bayannur areas of Inner Mongolia. Meanwhile, quantitive real-time quantity PCR (q-PCR) was applied to compare and quantitatively analyze the predominant species in traditional dairy products. The results showed as follows:A total of 202 strains of lactic acid bacteria were isolated from samples of two areas by using pure culture method. All of isolates were identified into 4 genus and 16 species or subspecies according to the 16S rRNA gene sequences analysis.Seventy eght isolates from 34 samples of Baotou were identified into 12 species or subspecies of lactic acid bacteria, including Lac. lactis subsp. lactis (18 strains, account for 23.08% of the total isolates), Leu. mesenteroides (18 strains, account for 23.08%), L. plantarum (14 strains, account for 17.95%), Leu. pseudomesenteroide (8 strains, account for 10.26%), L. helveticus (6 strains, account for 7.69%), L. kefiranofaciens (5 strains, account for 6.41%), L. paracasei (3 strains, account for 3.85%), E. faecium (2 strains, account for 2.56%) and E.faecali、E. durans、Leu. lactis、L. buchneri (account for 1.28% respectively). Lac. lactis subsp. lactis and Leu. mesenteroides were the predominant species of in these samples.One hundred and twenty four isolates from 35 samples of Bayannur were identified into 12 species or subspecies, including Lac. lactis subsp. lactis (48 strains, account for 38.71% of the total isolate), L. plantarum (32 strains, account for 25.81%), Leu. mesenteroides (22 strains, account for 17.74%), L. paracasei (6 strains, account for 4.84%), L. helveticus (5 strains, account for 4.03%), L. rhamnosus (3 strains, account for 2.42%) and L. brevis, L. diolivorans (2 strains, account for 1.61% respectively) and Leu. pseudomesenteroide、E. durans、E. sulfur ous、L. buchneri (1 strains, account for 0.81% respectively). Lac. lactis subsp. lactis and L. plantarum were the predominant species of samples.q-PCR was performed to quantize the predominant species of traditional dairy products. The results showed that the concentration of Lac. lactis subsp. lactis and L. plantarum in yogurt and cream were significantly higher in cheese of Baotou(p<0.05). The concentration of Leu. mesenteroides in yogurt was remarkably higher in cream and cheese of Baotou(p<0.05); The concentration of Leu. mesenteroides and L. plantarum in yogurt and cream were significantly higher in cheese of Bayannur (p<0.05). The concentration of Lac. lactis subsp. lactis in yogurt was remarkably higher in cream and cheese of Bayannur(p<0.05); The relationships of the number of three predominant species in traditional dairy products were Lac. lactis subsp. lactis> L. plantarum> Leu. mesenteroides.In this study, the species of lactic acid bacteria isolates and predominant species were analogous in traditional dairy products from Baotou and Bayannur areas due to the near geographical regions, where climate and geographical environment, the nomads living habits and the making craft of traditional dairy products were same. However, the concentration of predominant species exsisted distinct differences (p<0.05)。...