一株广谱抑菌活性乳酸菌的筛选及特性研究

【目的】从贵州剑河采集的传统自然发酵豆酱中分离筛选具有广谱抑菌效果的乳酸菌,并进行肠道益生特性的研究。【方法】通过抑菌试验分离筛选得到菌株DJ-04,对其进行人工胃肠液耐受性、胆盐耐受性和渗透压耐受性的研究,并对其进行生理生化鉴定和16S r RNA鉴定。【结果】菌株DJ-04对大肠杆菌、沙门氏菌、金黄色葡萄球菌、志贺氏菌和铜绿假单胞菌的生长有很好的抑制作用;在p H值为2.5的人工胃液中处理3 h活菌数达到107 CFU/m L以上;在人工肠液中处理3 h活菌数达到108 CFU/m L以上,对人工胃肠液表现出良好的耐受性。能耐受一定浓度的牛胆盐,在质量浓度0.2 g/100 m L的牛胆盐环境中活菌数可达到107 CFU/m L;具有较高的渗透压耐受能力,在Na Cl质量浓度为10 g/100 m L的液体MRS中培养24 h后,活菌数仍在107 CFU/m L以上。经鉴定,DJ-04为植物乳杆菌。【结论】植物乳杆菌DJ-04具有良好的人工胃肠液耐受性以及耐胆盐和耐渗透压能力,具有肠道益生菌的潜能。

Isolation of a broad-spectrum antibacterial lactic acid bacterium and evaluation of probiotic properties

Objective] This study wanted to isolate and evaluate the probiotic properties of a broad-spectrum antibacterial lactic acid bacterium from Chinese traditional fermented soybean paste which was sampled from Jianhe country, Guizhou Province. Methods] The strain DJ-04 was screened by antibacterial activity test, which was identified by physiological and biochemical characteristics and classification of 16S rRNA. The strain was examined for a series of assays including tolerance to artificial gastric intestinal juice, bile salt, and osmotic pressure. Results] The strain DJ-04 was identified as Lactobacillus plantarum. It had an antibacterial activity against five pathogenic bacterium, including Escherichia coli, Salmonella sp., Staphylococcus aureus, Shigella sp., and Pseudomonas aeruginosa. DJ-04 had a strong tolerance to acid. The number of viable cells after 3 hours of incubation in pH 2.5 reached more than 107 CFU/mL. DJ-04 had a strong tolerance to artificial gastric intestinal juice since no significant changes were observed after 3 hours of incubation. The number of viable cells after 24 hours of incubation in 0.2 g/100 mL bile salt was above 108 CFU/mL. In addition, the number of viable cells after 24 hours of incubation in MRS containing 10 g/100 mL NaCl was more than 107 CFU/mL. Conclusion] The isolated Lactobacillus plantarum DJ-04 had good tolerance to artificial gastric intestinal juice, bile salt, and osmotic pressure, suggesting that it could be a potential probiotics candidate for beneficial use.