益生菌Gan-1的鉴定、理化特性及其降胆固醇作用

从啤酒样品中分离出一株具有较强的耐酸、耐盐、耐胆盐及降胆固醇能力的细菌菌株Gan-1。利用多相分类方法，即通过形态特征、生理生化特性以及16S rRNA核酸序列分析，鉴定菌株Gan-1为干酪乳杆菌（Lactobacillus casei Gan-1）；采用MRS-Broth培养基，模拟人体胃酸环境、渗透压环境和胆盐环境，测定菌株Gan-1在酸性及高胆盐环境作用下菌株Gan-1的生长状况；结果表明，菌株能够耐受pH3的环境、低于6%NaCl的高渗环境以及低于2.0%胆盐环境；菌株具有降解胆固醇的能力，培养至24h时，降解的胆固醇达24%。

Identification, Physico - chemical Characteristics of Strain Gan - 1 and its Effect of Cholesterol Reducing in Vitro

A strain Gan - 1 which has the strong resistant ability for acid, salt, and bile salt and the good cholesterol reducing was screened from beer samples. The morphological, physiological, biochemical characteristics and 16S rRNA gene sequence of the strain Gan - 1 were analyzed. Then the strain Gan - 1 was identified as Lactobacillus casei Gan - 1 by polyphasic taxonomy method. By stimulating human gastric acid and intestinal bile salt condition, the viability of Gan - 1 strain during exposure to acid MRS broth, high salt MRS broth and bile salt MRS broth were determined, respectively. Then the bile salt hydrolase activity of Gan - 1 strain, degradation of bile salt and cholesterol precipitation were measured in this bile salt concentration. The results show that the strain Ganl has tolerance capability to the pH = 3, 6% salt and 0.3% bile salt environment and can reduce cholesterol. In MRS medium with cholesterol, strain Gan - 1 degrades 24% of cholesterol.