Isolation And Identification Of Lactic Acid Bacteria From Traditional Fermented Milk In Eastern Inner Mongolia

In this study, microbiological compositions of 182 traditional fermented milk samples collected from three regions in eastern Inner Mongolia were analyzed. 768 strains of lactic acid bacteria (LAB) were isolated from these samples and then identified using 16S rRNA sequencing analysis.The counts of LAB in 182 samples were range from 1.10×104 to 1.66×109cfu/mL. 768 strains of LAB were isolated on MRS agar and M17 agar, from 182 fermented milk samples, including 495 strains of rod, 273 strains of cocci. 487 strains were isolated from MRS agar, thereinto, 351 strains of rod, 136 strains of cocci; 281 strains were isolated from M17 agar which has 144 strains of rod and 137 strains of cocci.The identification results showed that Lactobacillus(L.) helveticus, Lactococcus(Lc.) lactis subsp. lactis, L. casei and Leuconostoc(Leu.) mesenteroides subsp. mesenteroides were the predominant species among all isolates, accounting for 19.92%, 17.19%, 13.80%, 12.63%, respectively. Moreover, L. diolivorans(8.85%) and L. plantarum(8.85%) were major species. The other isolates were identified as L. kefiri, L. parabuchneri, L. reuteri, L. kefirgranum, L. kefiranofaciens subsp. kefirgranum, L. pontis, L. hilgardii, L. brevis, L. rhamnosus, L. curvatus, L. acetotolerans, L. delbrueckii subsp. bulgaricus, L. fermentum, Streptococcus(S.) thermophilus, Enterococcus(E.) durans, E. faecium, E. italicus, Leu. pseudomesenteroides, Leu. Lactis and Lc. raffinolactis.The composition of LAB in the samples and predominant species were different in three regions of eastern Inner Mongolia. 112 strains of LAB (10 species) were isolated from 29 samples collected from Xilinguole. Among them, Lc. lactis subsp. lactis(28.57%) and Leu. mesenteroides subsp. mesenteroides(25.00%) were the predominant species, and L. helveticus, L. diolivorans and L. casei were major species, accounting for 13.39%, 11.61% and 10.71%; 299 strains of LAB (20 species) were isolated from 73 samples collected from Hulunbeier, of which L. helveticus(22.74%) and L. casei(20.74%) were predominant species, and L. diolivorans(10.70%), L. plantarum(10.37%) were major species; 357 strains of LAB (25 species) were isolated from 80 samples collected from Chifeng, of which Lc. lactis subsp. lactis(22.69%) and L. helveticus(19.61%) were the predominant species, and Leu. mesenteroides subsp. mesenteroides, L. casei and L. plantarum were major species, accounting for 12.89%, 8.96% and 8.68% respectively.Overall, the separation condition on MRS agar was different from M17 agar. Among the 26 species identified, 25 species were from MRS agar, whilst 22 species were from M17 agar. The LAB species separated from MRS involved the species separated from M17 except E. italicus (1 strain).