副干酪乳杆菌的分离鉴定及肠道耐受性研究

Isolation, identification, and growth tolerance characteristic of Lactobacillus paracasei

本研究对西藏传统乳制品中分离的35株乳酸菌进行16S rDNA序列分析,其中15株乳酸菌鉴定为干酪乳杆菌或副干酪乳杆菌群,通过recA基因序列分析后,进一步将其中5株归为副干酪乳杆菌。针对这5株副干酪乳杆菌进行耐受性评价,试验结果表明5株副干酪乳杆菌均具有较高的酸耐受性,其中副干酪乳杆菌KY1、KY2的耐受性最为突出。其在pH值为3.0的条件下处理3 h存活率可分别达到31.7%和30.9%,在高胆盐条件下处理4 h后存活率分别可达69.1%和64.9%,在人工胃液中3 h存活率可达15.1%和13.2%,人工肠液8 h存活率分别可达48.9%和48.3%,意味着这两株乳酸菌具有一定潜在的应用前景。

In this study, 35 strains of Lactic acid bacteria(LAB) isolated from traditional dairy products in Tibet were identified by 16 S rDNA gene sequencing and 15 strains have been belonging to the Lactobacillus casei or Lactobacillus paracasei. Afterwards, 5 strains were further classified as Lb. paracasei by recA sequence analysis and tolerance evaluation assays of this these strains were carried out. The results showed that all Lb. paracasei had high acid tolerance, and the tolerance of Lb. paracasei KY1 and KY2 were more prominent. Livability can be up to 31.7%and 30.9% in p H 3.0 for 3 h, and the 0.3% bile salt resistant rate were 69.1% and 64.9%, respectively.The tolerance rate in simulated gastric fluid were 15.1% and 13.2%, and tolerance rate in intestinal fluid for 8 h were 48.9% and 48.3%. Therefore, these two strains have a certain potential application prospect in dairy industry.