Department of Microbiology, School of Life Sciences, DAICENTER (DBT-AIST International Centre for Translational and Environmental Research) and Bioinformatics Centre, Sikkim University, Gangtok, 737102, Sikkim, India.
World J Microbiol Biotechnol. 2022 Jan 6;38(2):25. doi: 10.1007/s11274-021-03215-y.
A total of 272 isolates of lactic acid bacteria (LAB) were isolated from 22 samples of naturally fermented milk products of Sikkim in India viz. dahi, soft-variety chhurpi, hard-variety chhurpi, mohi and philu, out of which, 68 LAB isolates were randomly grouped on the basis of phenotypic characteristics, and were identified by 16S rRNA gene sequence analysis. Leuconostoc mesenteroides was the most dominant genus, followed by Leuc. mesenteroides subsp. jonggajibkimchii, Lactococcus lactis subsp. cremoris, Lc. lactis, Lc. lactis subsp. hordniae, Lc. lactis subsp. tructae, Enterococcus faecalis, E. italicus and E. pseudoavium. LAB strains were tested for probiotics attributes by in vitro and genetic screening, based on marker genes. LAB strains showed tolerance to pH 3.0, bile salt, resistance to lysozyme and β-galactosidase activity. Enterococcus faecalis YS4-11 and YS4-14 and Lactococcus lactis subsp. cremoris SC3 showed more than 85% of hydrophobicity. Genes clp L and tdc encoding for low pH tolerance, agu A and Ir1516 encoding for bile tolerance, LBA1446 gene encoding for BSH activity, map A, apf, mub 1 and msa encoding for mucosal binding property were detected. Gene mesY for bacteriocin production was detected only in Leuconostoc spp. Based on the in vitro and genetic screening of probiotic attributes, Leuc. mesenteroides; Leuc. mesenteroides subsp. jonggajibkimchii and Lc. lactis subsp. cremoris were tentatively selected for possible probiotic candidates.
从印度锡金的 22 份天然发酵乳制品样本（印度酸奶、软奶酪、硬奶酪、莫希和菲卢）中分离出 272 株乳酸菌（LAB），其中 68 株 LAB 分离株根据表型特征随机分组，并通过 16S rRNA 基因序列分析进行鉴定。肠膜明串珠菌是最主要的属，其次是肠膜明串珠菌 jonggajibkimchii 亚种、乳球菌乳脂亚种、乳球菌 lactis、乳球菌 lactis hordniae 亚种、乳球菌 lactis tructae 亚种、粪肠球菌、伊氏肠球菌和假鸟肠球菌。根据标记基因，通过体外和遗传筛选测试 LAB 菌株的益生菌特性。LAB 菌株表现出对 pH3.0、胆盐的耐受性，对溶菌酶和β-半乳糖苷酶活性的抗性。粪肠球菌 YS4-11 和 YS4-14 和乳球菌乳脂亚种 SC3 表现出超过 85%的疏水性。检测到编码耐低 pH 的 clp L 和 tdc 基因、编码耐胆盐的 agu A 和 Ir1516 基因、编码 BSH 活性的 LBA1446 基因、编码黏膜结合特性的 map A、apf、mub 1 和 msa 基因。仅在肠膜明串珠菌中检测到编码细菌素的 mesY 基因。基于益生菌属性的体外和遗传筛选，暂定选择肠膜明串珠菌、肠膜明串珠菌 jonggajibkimchii 亚种和乳球菌乳脂亚种 cremoris 作为可能的益生菌候选物。
