产类细菌素乳酸菌的筛选及培养条件优化

Study on Screening of Bacteriocin- producing Lactobacillus and Optimization of Culture Conditions

从紫花苜蓿青贮、牛奶及奶酪、酸菜中的分离到4株可产生类细菌素菌株，即戊糖乳杆菌（Lactobacilluspentosus）、植物乳酸菌（Lactobacillusplantarum）、戊糖片球菌（Pediococcuspentosaceus）、丙酸杆菌（Propionibacterium）。粗提4株细菌的发酵液对金黄色葡萄球菌有较强的抑制生长作用，对大肠杆菌的抑制作用较弱。4株分离菌类细菌素在80℃热处理15min后活性基本不变，100oC处理15min仍保持一定活性；在pH3～5范围内抑菌活性较强。胃蛋白酶、胰蛋白酶均可使该类细菌素完全失活；酸性蛋白酶不能使其失活。对分离株戊糖乳杆菌培养条件优化后，在30℃（pH值为6．0）条件下，选择碳氮质量分数为5％、碳氮质量比为3：2，添加MgS040．07g／100ml，MnSO4 0．05g／100ml，0．2ml／100mlTween-80有利于类细菌素的产生，抑菌直径可达18．2mm，是传统培养基配方抑菌效果的1．2倍。

Four Lactobacillus strains, which produce bacteriocin - like substance, were isolated from Medicago sativa silage, milk, cheese, and pickles. They are Lactobacillus pentosu, Lactobacillus plantarum, Pediococcus pentosaceus, Propionibacterium. Fermentation liquids exhibits strong inhibitory activity against staphylococcus au- reus, but less obvious to E. coli. Their Bacteriocins were resistant to temperature and pH values , but decreased to proteolytic enzymes. Culture medium was optimized and it was much more suitable for the growth. By incubating the Lactobacillus pentos can produce more bacteriocin - like substance in condition of 3：2 carbon - nitrogen mass ratio（C / N）, 0. 07 g/100ml MgSO4,0. 05 g/100ml MnSO4, 0. 2 ml/10Oml Tween-80. It was 1. 2 times than traditional formula could.