Purification and Antibacterial Properties of Bacteriocin Produced by Lactobacilus fermentum Isolated from Pickled Vegetables

The aim of this study was to screen and identify strains producing bacteriocin(named BLF52)with broad-spectrum resistance to foodborne pathogens from Chinese traditional fermented vegetables,and to isolate and purify the bacteriocin and analyze its antibacterial characteristics. Molecular sieve gel filtration chromatography and semi-preparative high-performance liquid chromatography(RP-HPLC)were used to purify bacteriocin and the molecular weight was determined by Tricine-SDS-PAGE. A bacteriocin-producing Lactobacilus fermentum CH-16 strain was isolated. The highest inhibition of S. aureus(875 AU/mL)was noted at early stationary phase after 24~30 h of growth in MRS medium at 34 ℃. BLF52 was purified to homogeneity and its molecular mass was 5.6 kDa. It was stable in the range of 40~80 ℃(30 min)and pH2.0~7.0(2 h). After treatment with pepsin,papain,trypsin and proteinase K,the antibacterial activity of BLF52 was completely lost,and α-amylase had no effect on it,indicating that BLF52 had typical bacteriocin characteristics. BLF52 exhibited a broad antimicrobial spectrum against food-borne spoilage and pathogenic bacteria such as Listeria monocytogenes,Staphylococcus aureus,Bacillus cereus,Salmonella typhi,Pseudomonas aeruginosa,Escherichia coli,and Vibrio parahaemolyticus. Bacteriocins BLF52 inhibitted the growth of S. aureus in culture through bactericidal mode. BLF52 has the potential to be developed as a food preservative suitable for acidic or neutral foods.