Isolation And Identification Of Lactic Acid Bacteria From Dairy And Dairy Products In The Bank Of Yimin And Hailaer River Pastoral Area And Screening Of Probiotic In Vitro

In this study, lactic acid bacteria were isolated from 61 samples of dairy and dairy products, which collected from three countysides of the bank of Yimin river and four countrysides of Hailaer river in Inner Mongolia. And screening probiotic from these stains. 33 strains of lactic acid bacteria were isolated. And among of them 12 are bacilli and 21 are cocci. According to their characteristics of morphology, physiology and biochemistry, sugar fermentation and amino acid composition of cell wall of bacteria, they were ascribed to 4 genus of Lactobacillus, Lactococcus, Enterococcus and Leuconostococcus , containing with 13 species.But, there are 4 strains were not determined both in genus and species in this study. In bacilli, 4 strains are Lactobacillus plantarum, 2 strains are Lactobacillus case, 2 strains are Lactobacillus helveticus, 2 strains are Lactobacillus curvatus, 1 strain is Lactobacillus coryniformis subsp. Coryniformis, 1 strain is Lactobacillus zeae.In cocci, 5 strains are L.lactis subsp.lactis or L.lactis subsp.diacetylactis, 4 strains are L.lactis subsp. Cremoris, 2 strains are L. raffinolactis, and E. faecalis, L.lactis, L.mesenteroides, L.mesenteriodes subsp. Mesenteroides is every one. In lactobacillus, the percent of Lactobacillus plantarum is 33.33 . In ococcus, the percent of Lactococcus is 52.33 . So Lactobacillus plantarum and Lactococcus are dominant bacteria. Organic acid that produced by most of these strains had better bacteriostasis. And L.lactis CB20-2 could produce bacteriocin in the course of metabolize. 10 strains can resist to acid(pH3). And, in the experiment of resistant to bile,the ratio of growth of 10 strains is surpass 3.0%. Most of strains that were experimented them had resistance to penicillin G, ampicillin, acetylspiramycin, sulfomethorxazole, ciprofloxacin and norfloxacin. Mass of stains had susceptibility to other antibiotics that were selected. The strains that were experimented showed adhesion to HT-29 cell, but the adhesion is poor. The number of adhesion was from 0.09 to 1.26.