粪肠球菌EF-ZA1107-06的安全性评价及益生特性研究

Safety Evaluation and Probiotic Characteristics of Enterococcus faecalis EF-ZA1107-06

从广州某1月龄婴儿粪便中分离得到一株肠球菌,经鉴定为粪肠球菌,命名为Enterococcusfaecalis EF-ZA1107-06,对该菌株进行体内外安全性评价和体外益生特性研究。结果表明:EF-ZA1107-06不产生硝基还原酶,无溶血活性,对多类抗生素表现高敏感且不含质粒,小鼠经口急性无毒,确定该菌株为食用安全菌;该菌具有良好的胃肠液耐受能力,连续暴露于人工唾液10min、人工胃液2h、人工肠液3h后,其存活率仍在65%以上,与Lactobacillusrhamnosus GG(LGG)相当;该菌可抑制大肠杆菌、沙门氏菌、铜绿假单胞菌、白色念珠菌、单增李斯特菌、金黄色葡萄球菌的生长,其上清液对大肠杆菌的抑制效果显著强于LGG;EF-ZA1107-06上清液、菌悬液和裂解液均有一定的DPPH自由基清除能力、羟自由基清除能力,且活菌数为2×10^(8) CFU/mL的菌悬液对DPPH自由基的清除率可达(93.16±0.17)%,对羟自由基的清除率为(90.48±1.12)%;活菌数为2×10^(8) CFU/mL的发酵液的胆固醇清除率为(44.29±0.30)%,具有较强的降胆固醇能力。

Enterococcuswas isolated from 1-month-old baby feces in Guangzhou and the strain was identified as Enterococcus faecalis by molecular biology and was named Enterococcus faecalis EF-ZA1107-06. The strain was evaluated for its safety and some probiotic potential properties. The results show that the strains does not produce nitroreductase and has no hemolytic activity. It is highly sensitive to many kinds of antibiotics, does not contain plasmids, and has no acute toxicity to the mice. EF-ZA1107-06 was proved as an edible safe strain. High tolerance was observed by EF-ZA1107-06 strain for simulated gastrointestinal condition. After continuous exposure to simulated saliva for 10 min, simulated gastric juice for 2 h, and simulated intestinal juice for 3 h, the survivability was still above 65%, which was comparable to that of Lactobacillus rhamnosus GG(LGG). EF-ZA1107-06 can inhibit the growth of Escherichia coli, Salmonella, Pseudomonas aeruginosa, Candida albicans, Listeria monocytogenes,Staphylococcus aureus. The inhibitory effect of its supernatant on Escherichia coli is significantly stronger than that of LGG. The supernatant, lysate and suspension of the EF-ZA1107-06 strain all have certain DPPH free radical scavenging capacity and hydroxyl radical scavenging ability. DPPH free radical scavenging rate of 2×10^(8)CFU/mL EF-ZA1107-06 suspension is(93. 16±0. 17)%. The hydroxyl radical scavenging rate of the suspension is(90. 48±1. 12)%. The cholesterol removal rate of 2×10^(8)CFU/mL EF-ZA1107-06 fermentation broth is(44. 29±0. 30)%.The EF-ZA1107-06 strain has high cholesterol scavenging ability.