%0 Journal Article
%T Isolation and Partial Characterization of a Bacteriocin Produced by a Newly Isolated Bacillus megaterium 19 Strain
%A Rowaida Khalil
%A Yasser Elbahloul
%A Fatima Djadouni
%A Sanaa Omar
%J Pakistan Journal of Nutrition
%D 2009
%I 
%X A Bacillus megaterium 19 strain isolated from a mixture of fermented vegetable wastes, produced a bacteriocin that displayed a wide spectrum antimicrobial activity against food-spoilage microorganisms and possessed a bactericidal mode of action. The bacteriocin activity against Salmonella typhimurium and Staphylococcus aureus attained its maximum value during the mid stationary phase. Maximal bacteriocin activity (93% growth reduction) was achieved using MRS broth, at initial pH of 5.5-6.5 and at 30ˇăC incubation temperature. High levels of bacteriocin activity (up to 85% growth reduction) were detected under limited or reduced oxygen levels. The inhibitory activity increased in mMRS broth with 4% sucrose and (0.10%) beef extract. The bacteriocin was thermally stable over a wide temperature range up to 100ˇăC for 15 min and retained its activity at acidic and neutral pH values, but not at alkaline pHs. Full bacteriocin activity was expressed after 30 days of storage at 4ˇăC, for 15 min of exposure to UV light. The bacteriocin was amylase and lipase sensitive, however, treatment with proteolytic enzymes resulted in a remarkable stability. SDS-PAGE analysis of the partially purified bacteriocin revealed an apparent molecular weight ranging from 3.496 to 6.512 kDa. The strain may have a potential use as food biopreservative, because of its promising thermostable technological properties and broad antimicrobial spectrum.
%K indicator organisms
%K bacteriocin activity
%K Bacillus megaterium
%K growth media
%K pH
%K enzymes
%U http://docsdrive.com/pdfs/ansinet/pjn/2009/242-250.pdf