Antimicrobial substance against Escherichia coli O157:H7 produced by Lactobacfflus amylovorus ME1
2008
Jung, B.M. (RnD Center, Mail Dairies Co., Ltd., Pyungtaek, Republic of Korea) | Woo, S.G. (RnD Center, Erom Co., Ltd., Seongnam, Republic of Korea) | Chung, K.S. (Yonsei University, Wonju, Republic of Korea), E-mail: kschung@yonsei.ac.kr
A lactic acid bacterium producing an antimicrobial substance against Escherichia coli O157:H7 was isolated from raw milk and identified as Lactobacillus amylovorus ME-l. In addition to E. coli O157:H7, the antimicrobial Substance also inhibited the growth of Bacillus cereus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyrogenes, and Yersinia enterocolitica. The antimicrobial substance was stable at pH 2-12 and 121℃ for 15 min and insensitive to proteinase K, protease, amylase, and catalase. Purification of the antimicrobial Substance was conducted through methanol and acetonitrile/ethyl acetate extraction, ultrafiltration with a 500 Da cutoff, thin layer chromatography (TLC) with silicagel 60, and high performance liquid chromatography (HPLC) with a C∧18 reverse phase column. The λ∧max of the purified antimicrobial substance was determined as 192 nm by ultra violet (UV) scanning, while the molecular weight was estimated as 453 Da based on the mass spectrum. Accordingly, the current results suggest that the antimicrobial substance front the L. amylovorus ME-1 was not a bacteriocin, but rather a new non-proteinaceous substance distinct from acidophilin, acidolin, diacetyl, and reuterin.
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