一株强吸附胆固醇乳酸菌的分离鉴定及益生特性研究

Isolation, identification and probiotic properties of a lactic acid bacterium strain with strong cholesterol-adsorbing ability

以健康黔北黑猪肠道黏膜内容物、健康成年人粪便和自然发酵泡菜为原料,分离筛选筛选出具有强降胆固醇效果的乳酸菌,并对其进行形态学观察及分子生物学鉴定。结果表明,从猪肠道黏膜中分离得到1株具有强胆固醇吸附能力的菌株,编号为R-15,其被鉴定为植物乳杆菌(Lactiplantibacillus plantarum)。菌株R-15的胆固醇降解率与其生长量(OD600 nm值)正呈相关,主要机制是吸附作用。当吸附时间为4.0 h时,活菌与死菌的胆固醇吸附率相近(70%)。对抗生素敏感性存在差异,对诺氟沙星、环丙沙星、庆大霉素等抗生素耐药,存在多重耐药机制;可耐受30~45℃的温度,60℃热处理30 min其存活率在40%以上;经pH2、0.3%牛胆盐、人工胃肠液处理6 h后活菌数对数值分别减少1.34、2.05、1.54、1.05,表明该菌株具有一定益生特性。

The lactic acid bacteria strains with high cholesterol-lowering ability were isolated and screened out from intestinal mucosal contents of healthy Qianbei black pig, adult feces and naturally fermented pickles, and identified by morphological observation and molecular biology. The results showed that one strain of lactic acid bacterium with strong cholesterol-adsorbing ability was obtained from intestinal mucosa of pig, and numbered as R-15, which was identified as Lactiplantibacillus plantarum. The cholesterol-lowering rate of the strain R-15 was positively correlated with its growth amount(OD600 nm), and the main cholesterol-lowering mechanism was adsorption. The cholesterol-adsorbing rate of dead cell was 70% after adsorption for 4.0 h, which was similar to the living cell. There were differences in antibiotic sensitivity, the strain was resistant to antibiotics such as norfloxacin, ciprofloxacin and gentamicin, and had multiple drug resistance mechanism. The strain could tolerant temperature 30-45 ℃, and the survival rate was over 40% with 60 ℃ treatment for 30 min. After 6 h treatment with pH 2, 0.3% bovine bile salt and artificial gastroenteric fluid, the log values of viable counts decreased by 1.34, 2.05, 1.54 and 1.05, respectively, indicating that the strain had certain probiotic properties.