Purification and Characterization of Bacteriocin Produced by Bacillus subtilis R75 Isolated from Fermented Chunks of Mung Bean (Phaseolus radiatus)
Nivedita Sharma*, Riti Kapoor, Neha Gautam and Ranjana Kumari
Department of Basic Sciences, Dr. Y.S. Parmar University of Horticulture and Forestry Nauni, Solan (H.P.) 173 230, India
Article history:
Received: November 17, 2009
Accepted: April 23, 2010
Key words:
bacteriocin, purification, biopreservative, antimicrobial activity, indicator bacteria
Summary:
Food-grade bacteria capable of producing bacteriocin with desirable preservation attributes have been isolated from traditional Indian fermented food dal vari, which has not been investigated so far. Among different isolates, Bacillus subtilis R75, isolated on MRS agar, exhibited antagonism against a wide range of foodborne pathogens that cause serious spoilage. Extracellularly produced bacteriocin was purified by single step gel exclusion column chromatography. The purity rate and molecular mass of 12 kDa of this compound were determined using SDS-PAGE. Activity units (AU) of bacteriocin were increased in each step of purification, reaching up to 5·106 AU/mL. The increase in the activity units directly affected the antimicrobial activity of purified bacteriocin, resulting in an increase up to 200, 333 and 175 % of the inhibition zones against indicator bacteria. Continuous decrease in the number of viable cells of microorganisms within 10 h after adding purified bacteriocin proved its bactericidal action. It withstood very high temperature, up to 121 °C, for 10 min, wider pH range, from 4.0 to 11.0, complete inactivation in the presence of proteolytic enzymes and storage stability up to 2.5 months.
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