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Purification and characteristics of bifidocin A, a novel bacteriocin produced by Bifidobacterium animals BB04 from centenarians' intestine

Liu, Guorong, Ren, Li, Song, Zhenqin, Wang, Chengtao, Sun, Baoguo
Food control 2015 v.50 pp. 889-895
Bifidobacterium, EDTA (chelating agent), Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, adsorption, animals, anti-infective properties, bacteria, bacteriocins, cation exchange chromatography, cysteine, desorption, food industry, gels, heat stability, intestines, mechanism of action, molecular weight, nutritive value, pH, polysorbates, proteinases, reversed-phase high performance liquid chromatography, reversed-phase liquid chromatography, spoilage, urea, yeasts
Bacteriocin-producing strain BB04, isolated from centenarians' intestine and identified as Bifidobacterium animals, produced the maximum activity of bifidocin A (640 AU/ml) in MRS medium supplemented with 0.05% (w/v) l-cysteine hydrochloride in the mid-stationary phase of growth (i.e. after 32 h at 37 °C). The bacteriocin, with a molecular mass of 1198.68 Da, was successfully purified by a four-step procedure consisting of adsorption and desorption onto/from producer cells, cation-exchange chromatography, gel filter chromatography and reverse phase high-performance liquid chromatography (RP-HPLC). Purified bifidocin A exhibited a wide range of antimicrobial activity against many food-borne spoilage and pathogenic bacteria such as Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, as well as some yeast. The mode of action of bifidocin A was bactericidal with concomitant cell lysis. Also, bifidocin A was heat stable, pH resistant and protease sensitive. EDTA, Tween 80, Tween 20 and urea did not decrease the activity, whereas, SDS induced 36% activity loss. This is the first report on a bacteriocin produced by B. animals. And the characterization, antimicrobial spectrum and molecular mass of bifidocin A suggested that it was a novel bacteriocin with potential research and application value in food industry.