Abstract

IDENTIFICATION OF ENTEROCIN FROM ENTEROCOCCUS CASSELIFLAVUS ISOLATED FROM SOYBEAN

Rajarajan P.N.*, Rajeswari K., Jeganathan P., and Sumathy N.

ABSTRACT

Background: In the present study, Enterococcus casseliflavus was isolated from soybean and enterocin was produced. Partial purification of enterocin, its antibacterial activity, sensitivity to pH, temperature, organic solvents, metal ions, molecular weight determination and protein estimation were investigated. The objective of the present study is to isolate and identify Enterococcus species from soybean, isolation of food borne pathogens which act as indicator organism like Staphylococcus from raw milk, Bacillus subtilis from soil, Escherchia coli and Vibrio parahaemolyticus and Enterococcus faecalis from sewage water, Production and purification of bacteriocins, Determination of bactericidal activity of enterocins produced by enterococcus against food borne pathogens, Molecular weight determination of enterocin by SDS-PAGE, Estimation of protein by Lowry’s method and physical and biochemical characterization. Methods: The cell free neutralized supernatant was obtained by removing the cells by centrifugation and neutralizing it by adjusting the pH to 7. The cell free supernatant exhibited antibacterial activity against the food pathogens which were isolated from various sources. It inhibited the growth of Bacillus subtilis, Escherchia coli, Enterococcus faecalis and Vibrio parahaemolyticus but not Staphylococcus aureus. Enterocins were purified from the culture supernatant by ammonium sulphate precipitation and dialysis. Results: The molecular weight of the enterocin was determined by SDS-PAGE and was found to be 4000Da approximately. The amount of protein present in crude enterocin was estimated by Lowry’s method and was found to be 336μg/ml. The sensitivity of bacteriocin to various pH, temperature, organic solvents and metal ions was determined. The bacteriocin was stable at a pH range of 4-9 and at a temperature of 800C, 100oC and 1210C. Conclusion: The possible use of bacteriocins as food biopreservatives could lead to the replacement of synthetic chemical preservatives, which have their antimicrobial action reduced due the continued appearance of multiresistant microbial lineages.The isolated active compounds from Enterococcus casseliflavus was proteinaceous, heat stable. It was also stable and active over a wide pH range and had a bacteriocidal mode of action on various organisms. This enterocin was a low molecular weight protein and heat stable. So we can derive these under class II bacteriocins.

Keywords: Bacteriocins, Antimicrobials, Food Industry, Biopreservation.