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Propionicin HJ227, a bacteriocin produced by Propionibacterium freudenreichii KCCM 31227, was characterized, and bcteriocin activity was measured by the modified well-diffusion method using Micrococcus flavus KCCM 10240 as an indicator strain. Propionicin HJ227 was concentrated by 75% ammonium sulfate precipitation and dialyzed. This crude bacteriocin showed antibacterial activity against most propionibacteria and bacilli, Staphylococcus aureus KCCM 32359, Lactococcus lactis KCCM 32406, M. flavus KCCM 10240, and some pathogenic organisms. Antibacterial activity of propionicin HJ227 on sensitive cells disappeared completely by α-chymotrypsin treatment, which indicates its proteinaceous nature, whereas activity remained during treatments up to 100℃ for 30 min. Propionicin HJ227 was very stable over a pH range of 3.0 to 9.0 and was stable with all organic solvents examined. the bacteriocin exhibited a bactericidal mode of action against M. flavus KCCM 10240. Morphological changes were observed in exponential-phase indicator cells when propionicin HJ227 was added. The apparent molecular mass of propionicin HJ227 was estimated to be about 6-6.5 kDa by direct detection of bacteriocin activity after SDS-PAGE. Based on these results, propioncin HJ227 appears to differ from the bacteriocins so far characterized.
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