鲈鱼肠道来源降胆固醇乳酸菌分离筛选及其益生功能评价

Isolation, Screening, and Probiotic Function Evaluation of Lactic Acid Bacteria with Cholesterol-lowering Effects from the Intestinal Tract of Seabass

摘要:

该研究探讨了从健康鲈鱼肠道中筛选分离出高效降胆固醇的乳酸菌，通过菌株鉴定、耐酸、耐胆盐、疏水性、自凝聚力和代谢物抑菌性评价的测定，评价并考察其体外益生作用。采用胆盐水解酶测定和体外降胆固醇试验，筛选分离得到一株高效降胆固醇的菌株ZG2YLu05，其胆盐水解酶（BSH）粗酶活和胆固醇去除率分别为0.82 µmol/(h•mL)和50.09%；在pH 3.0的培养条件下培养8 h，菌株的耐酸存活率为83.33%；在胆盐浓度0.3%的培养条件下培养8 h，菌株的耐胆盐存活率高达89.31%；在二甲苯中菌株的疏水性为46.82%，静置24 h后菌株的自凝聚力为92.93%，说明菌株具有良好的黏附潜力；菌株代谢物对大肠杆菌、金黄色葡萄球菌和沙门氏菌都有明显的抑制作用；经形态学观察和16S rDNA鉴定为戊糖乳杆菌（Lactiplantibacillus pentosus）。该菌株能够作为潜在降胆固醇乳酸菌用于开发辅助降脂益生菌制剂的生产。

Abstract:

This study focused on the screening and isolation of lactic acid bacteria with high-efficiency cholesterol-lowering effects from the intestines of healthy seabass. The assessments of in vitro probiotic effects were carried out through strain identification, together with the evaluation of acid resistance, bile salt tolerance, hydrophobicity, self-cohesion, and the antibacterial properties of their metabolites. Bile salt hydrolase (BSH) assays and in vitro cholesterol reduction tests were performed, which led to the isolation of a high-efficiency cholesterol-lowering strain ZG2YLu05. This strain exhibited crude BSH activity with a value of 0.82 µmol/(h•mL), and a cholesterol removal rate of 50.09%. The acid-resistance survival rate of the strain was 83.33% when cultured at pH 3.0 for 8 h, while the bile salt-tolerance survival rate was 89.31% when cultured in 0.3% bile salt concentration for 8 h. The hydrophobicity of the strain in dimethylbenzene was 46.82% and its self-cohesion was 92.93% when left to stand for 24 h, which indicates that the strain has potentially good adhesion properties. The metabolites of the strain also showed significant inhibition of Escherichia coli, Staphylococcus aureus, and Salmonella. The strain was identified as Lactiplantibacillus pentosus through morphological observations and 16S rDNA sequencing. Therefore, this strain can be used as a potential cholesterol-lowering lactic acid bacteria for the development of complementary lipid-lowering probiotic preparations.