内蒙古传统乳制品中乳酸菌的分离鉴定及耐酸性能研究

Isolation, identification and acid tolerance of acid-tolerant lactic acid bacteria from traditional milk product in Inner Mongolia

目的筛选耐酸能力强、能耐受人体胃肠环境在肠道中存活的乳酸菌菌株。方法对采集自内蒙古地区牧民家庭中45份传统乳制品中的乳酸菌进行分离和和纯化,共分离出104株乳酸菌,并进行形态观察、碳水化合物代谢分析、16S r DNA序列分析、高通量耐酸性优良菌株的筛选和人工胃液耐受性分析等的研究。结果本研究共筛选到8株耐受人工胃液极佳的乳酸菌,经鉴定这些菌株为4株Lactobacillus plantarum(WHH727、WHH730、WHH777和WHH1118)、3株Lactobacillum fermentum(WHH734、WHH778和WHH868)和1株Lactobacillus acidophilus(WHH729)。其中,耐受人工胃液最佳的是L.fermentum WHH734,经p H为1.5的人工胃液处理2 h,存活率在86.32%,经p H为2.5的人工胃液处理2 h后,存活率为96.85%。结论菌株的分离鉴定以及高耐酸性菌株的筛选,对我国益生菌资源的保藏和开发有重要的意义。

Objective To screen acid–tolerant lactic acid bacteria strains, which can tolerate gastroenteric environment and survive in human intestine. Methods A total of 104 strains of lactic acid bacteria were isolated and purified from 45 samples of traditional milk products in Inner Mongolia, which were conducted morphological, physiological, biochemistry test, 16 S r DNA sequencing analysis, acid-tolerant test and artificial gastric juice resistance test. Results Totally 8 strains of lactic acid bacteria were screened to have excellent resistance in artificial gastric juice, in which 4 strains were identified as Lactobacillus plantarum（WHH727, WHH730, WHH777 and WHH1118）, 3 strains were identified as Lactobacillum fermentum（WHH734, WHH778 and WHH868） and one strain was identified as Lactobacillus acidophilus（WHH729）. Among that, L. fermentum WHH734 was the best strain for tolerance of artificial gastric juice. The survival rates were 86.32% in the screening experiment of resistance to the artificial gastric juice（p H 1.5, 2 h）, and 96.85% at p H 2.5. Conclusion The isolation and identification of strains and screening of high acid-tolerant strains have very important significance to the preservation and exploitation of probiotic resource.