一株泡菜产细菌素乳酸菌的鉴定

Identification of bacteriocin-producing Lactobacillus from pickle

乳酸菌所产细菌素可作为传统食物防腐剂的替代品,近几年国内的研究主要集中在产细菌素新菌株和高产菌株的筛选.以从西南地区泡菜汁中筛选出的一株产细菌素的乳酸菌QH 18-4为研究对象,根据形态特征和生理生化试验,结合16S rDNA序列分析,鉴定菌株QH 18-4(菌种编号:SICC 1.1438)为耐盐魏斯氏菌(Weissella halotolerans).测定菌株QH 18-4产细菌素的抑菌谱,菌株QH 18-4对大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、肠道沙门氏菌(Salmonella enterica)、单核细胞增生李斯特氏菌(Listeria monocytogenes)、枯草芽孢杆菌(Bacillus subtilis)、蜡样芽孢杆菌(Bacillus cereus)、绿脓假单胞杆菌(Pseudomonas aeruginosa)有不同程度的抑制作用.通过阳离子交换层析和分子筛层析分离了该细菌素,并通过SDS-PAGE确定其分子量(Mr)约为3.0×10^3.菌株QH 18-4所产细菌素对细菌具有广谱抑菌性,且抑菌活性较高.本研究所筛选的耐盐魏斯氏菌丰富了乳酸菌工业化生产的菌种资源,扩大了乳酸菌细菌素出发菌株的选择范围,具有较大应用潜力.

Bacteriocin produced by Lactobacillus can be used as a substitute for conventional food preservatives.Research in this area,therefore,has mainly focused on the screening of new,highly productive bacteriocinproducing strains.Here we describe one bacteriocin-producing strain,i.e.,QH 18-4(number of strains:SICC 1.1438),which was screened from pickle lixivium in southwest China.Strain QH 18-4 was classified as Weissella halotolerans,based on morphological characteristics and the results of physiological and biochemical tests and 16S rDNA sequencing.The bacteriostatic spectrum of bacteriocin produced by strain QH 18-4 was preliminarily determined,and response surface methods were used to optimize the production conditions for strain QH 18-4.Bacteriocin was purified by cation exchange chromatography and molecular sieve chromatography.Its molecular weight was determined by SDS-PAGE.This compound showed various inhibitory effects on Escherichia coli,Staphylococcus aureus,Salmonella enterica,Listeria monocytogenes,Bacillus subtilis,Bacillus cereus,and Pseudomonas aeruginosa.Its molecular weight(Mr)was determined to be approximately 3.0×10^3 by SDSPAGE.Bacteriocin produced by strain QH 18-4 exhibited potent broad-spectrum bacteriostatic activity.This research enriches the strain sources for the Lactobacillus industry and expands the screen range of Lactobacillus bacteriocin.The Weissella halotolerans screened in this study shows great application potential,enriches the resources of lactic acid bacteria in industrial production,and expands the selection range of LAB bacteriocinstarting strains.