具有降胆固醇功能的罗伊氏乳杆菌的筛选及其益生作用

为获得具有较强降胆固醇功能的益生菌株，试验从内蒙古呼伦贝尔满洲里通达牧场制作的奶豆腐中筛选分离菌株，并采用邻苯二甲醛法测定菌株降胆固醇的能力，从中选出降胆固醇能力强的菌株，通过形态学鉴定、生理生化及16S rDNA对菌株进行鉴定，并测定了其耐受酸、胆盐和胃肠液的能力。结果筛选分离出5株具有降胆固醇功能的菌株，其中一株菌对胆固醇降解能力最强，降解率达50.60%，经鉴定此株菌为罗伊氏乳杆菌（Lactobacillus reuteri），将其命名为HCS02-001（CGMCC No. 19746）；经对酸、胆盐及胃肠液的耐受试验，该株菌在pH 3.0和pH 2.0的环境中培养17 h后存活率分别为86.80%和85.52%；在0.30%、0.50%的胆盐浓度环境中培养17 h后存活率分别为97.42%和95.17%；在人工胃液中作用3 h，存活率为96.74%；在人工肠液中作用4 h，存活率高达98.41%。该研究筛选出了一株具有较好降胆固醇功能的罗伊氏乳杆菌（Lactobacillus reuteri），其具有较强的耐受酸、胆盐环境和胃肠液的能力，对关于降胆固醇功能方面的产品研究开发具有重要意义。

Screening for Cholesterol-lowering Lactobacillus reuteri Strains and Analyzing Their Probiotic Effectiveness

To obtain probiotic strains with significant cholesterol-lowering performance, strains were isolated from quark produced at the Litongda Pasture in Manzhouli, Inner Mongolia. The cholesterol-lowering ability of each strain was determined by the o-phthalaldehyde method, and the strains with strong cholesterol-lowering abilities were selected. The strains were identified based on the morphology, physiology, biochemistry, and 16S rDNA sequences, and their tolerance for acids, bile salts, and gastrointestinal juice was determined. Finally, five cholesterol-lowering strains were obtained, and one of them showed the best ability to lower the cholesterol level, with a degradation rate of 50.60%. This strain was identified as Lactobacillus reuteri, and named as HCS02-001 (CGMCC No. 19746). The results of the various tolerance tests were as follows. When the strain was cultured at pH 3.0 and pH 2.0 for 17 h, the final survival rates were 86.80% and 85.52%, respectively. Similarly, the survival rates were 97.42% and 95.17% after the strain was cultured for 17 h in 0.3% and 0.5% bile salts, respectively. In addition, the survival rates were as high as 96.74% and 98.41% after three hours of treatment in artificial gastric juice and four hours of treatment in artificial intestinal juice, respectively. In summary, a strain of Lactobacillus reuteri with good cholesterol-lowering performance and showing high tolerance for acids, bile salts, and gastrointestinal juices, had been identified. These findings are of great relevance to the research and development of cholesterol-lowering products.