Partial Characterization of an Anti-Listerial Bacteriocin from Enterococcus faecium CJNU 2524

Listeria monocytogenes is a representative foodborne pathogen and causes listeriosis. Enterococcus faecium CJNU 2524 was confirmed to produce a bacteriocin with anti-listerial activity. To establish optimal culture conditions for the production of the bacteriocin from E. faecium CJNU 2524, different media (MRS and BHI broth) and temperatures (25°C, 30°C, and 37°C) were investigated. The results showed that the optimal culture conditions were MRS broth and 25°C or 30°C temperatures. The crude bacteriocin was stable in a broad range of pH conditions (2.0-10.0), temperatures (60°C-100°C), and organic solvents (methanol, ethanol, acetone, acetonitrile, and chloroform). The bacteriocin activity was abolished when treated with protease but not α-amylase or lipase, indicating the proteinaceous nature of the bacteriocin. Finally, the bacteriocin showed a bactericidal mode of action against L. monocytogenes. Therefore, it can be a biopreservative candidate for controlling L. monocytogenes in dairy and meat products.