一株开菲尔乳杆菌的分离及特性研究

Isolation and properties of Lactococcuslactis kefiri

为了筛选益生乳酸菌,从云南传统发酵乳制品中分离到一株菌株,命名为JMCC0101,经形态学特征、16S r RNA基因序列及生理生化特性分析,鉴定为开菲尔乳杆菌(Lactobacillus kefiri)。该菌株对酸和胆汁均表现出了一定的耐受能力,在模拟人工胃液的环境中培养3 h后,活菌数接近于10~5 CFU/m L水平;而经1%牛胆汁作用3 h后,菌数还出现了微弱的增加。通过K-B法评价了其对30种抗生素的敏感性,发现其对27种常见抗生素均敏感。开菲尔乳杆菌JMCC0101可作为一株潜在的优良候选菌株进行深入研究。

In order to select probiotic, lactic acid bacteria, a predominant strain, named JMCC0101, was isolated from traditional fermented milk of Yunnan. This bacterial strain was identified as Lactococcuslactis kefiri based on its morphologic properties, 16S rRNA sequences, as well asphysiological and biochemical characteristics. The strain showed a certain degree of tolerance to acid and bile. After 3 h in a simulated gastric fluid, viable counts for the strain were maintained up to 105 CFU/mL. JMCC 0101 strain exposed to MRS broth supplemented with 1% oxgall for 3 h showed a slight increase in cell viability. Meanwhile, Caco-2 cells, a model for intestinal epithelial cells, were used to measure bacterial adhesive ability. JMCC0101 strain exhibited adherence to Caco-2 cells with an adhesion ratio of 0.59%. The minimum inhibitory concentration was used to evaluate antibiotic susceptibility of the isolate. This strain was found to be susceptible to 27 antibiotics. Thus Lactococcuslactis kefiri JMCC0101 is a good candidate for further investigation.