芒果源高降胆固醇乳酸菌的特性及其作用机制

Characterization and Mechanism of Lactic Acid Bacteria Isolated from Mango,with Cholesterol-Lowering Effects

目的:明确芒果源高降胆固醇乳酸菌去除胆固醇的机制,为以后应用于果汁发酵生产具有降胆固醇作用的果汁饮品提供优良的菌种。方法:对降胆固醇能力强的15个菌株进行体外耐受性及其降胆固醇吸附作用的研究,采用气-质联用色谱对体外耐受性好,降胆固醇能力高的菌株MPL1进行细胞脂肪酸组成研究。结果:12个菌株可耐受p H 1.0的极酸性环境,15个菌株在质量浓度0.3 g/100 m L的各种胆盐介质中生长良好;7个菌株在人工肠液中培养4 h后,存活率均在97%以上。菌株MPL1、MPL2、MPL5、MPL8和MPL16的生长菌体对胆固醇的去除量比休眠菌体和热灭活菌体多。菌株MPL1在胆固醇存在或没有胆固醇的培养基中生长,其细胞脂肪酸组成含量发生了变化,说明培养基中的胆固醇被菌株同化到细胞膜中。结论:15个高胆固醇降解乳酸菌中,有7个菌株可以体外高度耐酸、耐胆盐,能顺利通过胃部进入肠道环境并在肠道里良好生长。菌株MPL1通过同化和吸附胆固醇来去除胆固醇。

Objective： To understand the cholesterol removal mechanism of lactic acid bacteria isolated from mango,with cholesterol-lowering effects; to provide admirable lactic acid bacteria starters for fermentation of mango juice to obtain a kind of mango beverage with cholesterol-lowering effects. Methods： Fifteen strains with high removal rate of cholesterol were studied for their tolerance in vitro and cholesterol assimilation was determined. The cellular fatty acidscomposition of the strain MPL1 with high cholesterol-lowering effect and good tolerance was tested using GC-MS. Results： all 15 strains had tolerance characteristics against 0.3 g/100 m L bile salt, but only 12 strains could grow in the media with very low p H 1.0. The survival rate of 7 isolates was above 97% after incubation in artificial intestinal fluid.The cholesterol removal content of the growing cells of strains of MPL1, MPL2, MPL5, MPL8 and MPL16 was higher than that of the dead and resting cells of strains of MPL1, MPL2, MPL5, MPL8 and MPL16. Fatty acid composition of MPL1 showed changes in lipid profiles in cells grown in the presence of cholesterol compared with those grown without cholesterol. Fatty acid profiles suggested that cholesterol from the medium was incorporated into the cellular membrane.Conclusions： Among 15 strains with cholesterol-lowering effects, 7 strains could tolerate acid and bite salt, and they could survival in artificial gastric fluid and intestinal fluid. The strain MPL1 removed cholesterol through assimilation and absorption cholesterol.