乳酸菌产细菌素生物学特性的研究及培养条件的优化

Study on the biological characteristics of bacteriocin production by mixed fermentation and optimization of culture conditions

中文关键词:  乳酸菌  细菌素  抑菌活性  生物学特性  培养条件优化

英文关键词:Lactobacillus  bacteriocin  antibacterial activity  biological characteristics  culture conditions optimization

中文摘要:

      目的 研究乳酸菌产细菌素的生物学特性并优化培养条件。方法 将实验室保藏的EF2(植物乳杆菌)和PP2(嗜酸乳杆菌)2株乳酸菌进行混合发酵, 采用牛津杯法分析细菌素的生物学特性, 并通过单因素实验和正交实验优化了EF2和PP2混合发酵产细菌素的培养条件。结果 细菌素在酸性、中性、弱碱性条件下活性较强; 耐高温, 属于热稳定性物质, 它对胰蛋白酶、胃蛋白酶、蛋白酶K和中性蛋白酶敏感, 对α-淀粉酶和木瓜蛋白酶不敏感, 是广谱细菌素。EF2、PP2混合发酵产细菌素的最佳培养基成分为葡萄糖20 g/L、蛋白胨 12.5 g/L、牛肉膏15 g/L、酵母膏5 g/L、K2HPO4?3H2O 2 g/L、无水乙酸钠5 g/L、柠檬酸三铵2 g/L、MgSO4 0.2 g/L、MnSO4 0.05 g/L、Tween-80 2 mL/L、蒸馏水1 L。最佳培养条件为: 初始pH为6.5、接种量4%, 装液量100 mL/250 mL, 发酵温度35 ℃, 在此条件下, 细菌素抑菌活性比优化前提高了1.36倍。结论 乳酸菌EF2和PP2混合培养得到的细菌素为具有较好抗性的广谱细菌素, 并通过单因素实验和正交实验确定了2株乳酸菌混合培养产细菌素的优化条件。

英文摘要:

      Objective To study the biological characteristics of bacteriocin production by mixed fermentation and optimize the culture conditions. Methods After the mixed fermentation of Lactobacillus EF2 (Lactobacillus plantarum) and PP2 (Lactobacillus acidophilus)were preserved in laboratory, the biological characteristics of bacteriocin were analyzed by oxford cup method. The single factor and orthogonal experiment were used to optimize the culture conditions of bacteriocin production by mixed fermentation. Results The bacteriocin had the following characteristics: higher activity in acidic, neutral and weak alkaline, high temperature resistance, sensitive to trypsin, pepsin and proteinase K and neutral proteinase and insensitive to α-amylase and papain. The bacteriocin was broad-spectrum, it could inhibit both Gram-negative and Gram-positive bacteria. The optimal formula of bacteriocin production was glucose 20 g/L, peptone 12.5 g/L, beef extract 15 g/L, yeast extract 5 g/L, K2HPO4?3H2O 2 g/L, anhydrous sodium acetate 5 g/L, triammonium citrate 2 g/L, MgSO4 0.2 g/L, MnSO4 0.05 g/L, Tween-80 2 ml/L, water 1 L. The optimal fermentation conditions were: initial pH 6.5, inoculums dose 4%, the volume of liquid 100 mL/250 mL, fermented temperature 35 ℃, and the antibacterial activity increased by 1.36 times than non-optimized. Conclusion The bacteriocin produced by the mixed culture of Lactobacillus EF2 and PP2 is a broad-spectrum bacteriocin with good resistance, and the optimal conditions of bacteriocin production are obtained by single factor experiment and orthogonal experiment.