传统发酵乳品中产广谱细菌素乳酸菌选育

Breeding of broad-spectrum bacteriocin-producing lactic acid bacteria in traditional fermented dairy products

为选育产广谱细菌素乳酸菌,采用琼脂扩散法对甘肃牧区传统发酵乳品中分离纯化的96株乳酸菌进行了筛选,并确定产细菌素菌株,具有最佳抑菌效果的菌株经重离子束12C6+辐照诱变,再采用培养皿分区法进行6种指示菌广谱抑菌性能比较。结果表明,琼脂扩散法筛选出抑菌效果最佳的产细菌素菌株Lp1,经辐照诱变得到98株突变菌,选育出对大肠埃希氏菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、单核细胞增生李斯特氏菌(Listeria monocytogenes)、沙门氏菌(Salmonella)、志贺氏菌(Shigella)和克罗诺杆菌(Cronobacter)抑菌性能均明显优于出发菌株Lp1的5株突变株L088、L087、L063、L049、L010进行广谱抑菌试验,其中菌株L088和L063为广谱抑菌性能较好菌株,突变株L088对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高47.81%、33.28%、22.97%、45.25%、21.39%、40.21%,突变株L063对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高54.27%、29.18%、25.37%、58.03%、17.85%、42.13%。采用培养皿分区法可同时在1个培养皿中完成检测6种指示菌的抑菌试验,可高效筛选产广谱细菌素乳酸菌。

To breed broad-spectrum bacteriocin-producing lactic acid bacteria,96 strains of lactic acid bacteria isolated and purified from tradition fermented dairy products in Gansu province were screened by agar diffusion assay,and the bacteriocin-producing strains were determined.The strains with the optimal antibacterial effect were mutated by heavy ion beam 12C6+irradiation,and the broad-spectrum antibacterial performance on six indicator bacteria was compared by culture dish partition method.The results showed that the bactericin-producing strain Lp1 with the optimal bacteriostatic effect was selected,and 98 mutant strains were obtained by irradiation mutation.Five mutant strains(L088,L087,L063,L049,L010)with significantly better antibacterial performance against Escherichia coli,Staphylococcus aureus,Listeria monocytogenes,Salmonella,Shigella and Cronobacter were screened for broad-spectrum antibacterial performance,and were significantly better than those of the original strain Lp1.Among them,strains L088 and L063 had better broad-spectrum antibacterial performance,the radius of inhibition annular sector of the mutant strain L088 against 6 indicator bacteria increased by 47.81%,33.28%,22.97%,45.25%,21.39%,and 40.21%than that of the original strain Lp1 respectively,and the radius of inhibition annular sector of the mutant strain L063 against 6 indicator bacteria increased 54.27%,29.18%,25.37%,58.03%,17.85%,and 42.13%,respectively.The inhibition tests of 6 indicator bacteria could be completed in one Petri dish simultaneously,which could screen the broad-spectrum bacteriocin-producing lactic acid bacteria efficiently.