307-315 The objective of this
study was to provide molecular evidences for enterocin biosynthesis by Enterococcus
faecium MTCC 5153. The culture filtrate (CF) of E. faecium MTCC 5153 exhibited a broad inhibitory spectrum against
several enterococci, food-spoilage lactic acid bacteria (LAB) as well as
pathogenic Gram-positive bacteria. The antimicrobial compound present in the CF
showed the properties of class IIa bacteriocin. PCR was employed for taxonomic
identification and detection of genes coding for virulence factors and
different enterocins. Based on amplification of enterocin A (entA) gene by PCR, additional
characterization of enterocin A operon was carried out. Southern hybridization
confirmed the presence of chromosomally encoded enterocin A (entA) gene. These results suggest
distribution of conserved enterocin A operon among different strains of E. faecium. Tricine SDS-PAGE activity
gel assay in combination with mass spectral analysis indicated the production
of single enterocin of 4.8 kDa in size. Production of enterocin was carried out
using different sugars in tryptone, yeast extract (TYE) medium, under
microaerophilic condition and the antimicrobial activity in the range of 10-50 x103 arbitrary units per milliliter (AU mL-1) was
observed. This study indicates the potentiality of native isolate to produce
broad spectrum bacteriocin which can be used to deal with spoilage bacteria and
food-borne pathogens like listeria