一株鱼源植物乳杆菌的部分生物学特性研究

Research on some biological characteristics of a Lactobacillus plantarum strain isolated from fish

为了从实验室现有的3株乳酸菌中筛选出对维氏气单胞菌、嗜水气单胞菌抑菌效果较好的乳酸菌,并对其部分生物学特性进行研究,试验采用打孔方法从3株菌中筛选出抑菌效果较好的菌株,并对该菌株在不同胆盐浓度、不同pH值、高温环境下的生长情况以及对胰蛋白酶的耐受能力和生长能力进行测定。结果表明：3株乳酸菌中,仅植物乳杆菌C20015对致病菌均有抑制作用,其余两株菌对其无抑制作用;C20015在抗逆性试验中,随胆盐浓度的增加,其活菌数下降,但活菌数均达到1.0×10^5cfu/mL以上;在pH值为2时,C20015的活菌数明显下降,当pH值大于3时,活菌数均达到1.0×10^6cfu/mL以上;在耐高温试验中,50℃时C20015活菌数下降不明显,但60℃以上几乎无菌生长;胰蛋白酶对活菌数无影响;植物乳杆菌C20015在0-10 h内快速增长,从10小时开始进入生长稳定期,直到20小时细菌数达到最大值3.6×10^9cfu/mL。说明植物乳杆菌C20015对水产类致病菌有一定的抑制作用,且对低pH值、高浓度胆盐、胃蛋白酶具有一定的耐受能力,有望应用于水产养殖饲料。

The aim of the present study was to screen out the Lactobacillus with good bacteriostasis effect against Aeromonas veronii and Aeromonas hydrophila from three strains of Lactobacillus available in the laboratory,and to study some biological characteristics of the Lactobacillus.The strains were screened out by plate stiletto method.And the tolerance of the strains to different bile salts,different pH,high temperature,trypsin and growth ability were detected.The results showed that among the three strains of Lactobacillus plantarum,only L.plantarum C20015 had inhibitory effects on both pathogenic bacteria,while the other two strains had no inhibitory effects.In the stress resistance test,with the increase of bile salt concentration the viable numbers of L.plantarum C20015 decreased,but still reached more than 1.0 × 10^5 cfu/m L.In the condition of pH = 2,the number of viable bacteria decreased significantly,when pH 〉3,the number of viable bacteria was above 1.0 ×10^6 cfu/m L.In the high temperature tolerance test,the number of viable bacteria did not decrease obviously at 50 ℃,but the aseptic growth was above 60 ℃.In addition,trypsin had no influence on the number of viable bacteria.L.plantarum C20015 grew rapidly in the period of 0-10 h,and reached the growth stable stage at 10 h until the maximum number of bacteria reached the maximum of 3.6×10^9 cfu/m L at 20 h.The results indicated that L.plantarum C20015 had a certain inhibitory effect on aquatic pathogenic bacteria and it had tolerance to low pH,high bile salt and pepsin to some extent,which was promising to be applied in aquaculture as a novel feed additive.