Property and Antibacterial Spectrum of Partially Purified Enterocin Produced by Entrocinogenic Enterococcus faecalis Isolated from the Gut of Cockroach

Abstract

Enterocins are small, heat stable and antimicrobial agents are directed against a broader spectrum of bacteria. Isolation, partial characterization and antibacterial activity of partially purified enterocin from Enterococcus faecalis form the aim of this study. The protein content of crude enterocin of the enterocin from highest producing strain was 16.6 mg/ml and its activity was 170 AU/ml. The antibacterial activity of crude enterocin produced by Enterococcus faecalis was tested on both Gram-positive bacteria which include Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus and Bacillus cereus, while Gram-negative bacteria were Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, Proteus mirabilis, Listeria monocytogenes and Salmonella Typhi. The effect was pronounced on Gram-negative than Gram-positive pathogens. The enterocin was stable at 40, 50, 60 and 70oC and over a pH range between 4.0 and 8.5. It has bactericidal effect and cause rapid inhibition of the growth of the sensitive strains. No change was observed in the enterocin bioactivity after treatment with sodium chloride, magnesium chloride, sodium dodecyl chloride, ethylene diamine tetra-acetic acid and urea. In conclusion, since it can withstand a broad range of temperature and pH, it can be used as biocontrol of both pathogenic and spoilage organisms.