Journal of
Microbiology and Antimicrobials

  • Abbreviation: J. Microbiol. Antimicrob.
  • Language: English
  • ISSN: 2141-2308
  • DOI: 10.5897/JMA
  • Start Year: 2009
  • Published Articles: 166

Full Length Research Paper

Purification of a bacteriocin produced by Enterococcus faecium and its effectiveness for preservation of fresh-cut lettuce

Bellei B.1, Miguel M.2, Mere Del Aguila E. M.1*, Silva J. T.1 and Paschoalin V. M. F.1
  1Universidade Federal do Rio de Janeiro, Instituto de Química, Departamento de Bioquímica, Brazil. 2Instituto de Microbiologia Prof. Paulo de Goes, Laboratório de Microbiologia de Alimentos, Rio de Janeiro, RJ, Brazil.
Email: [email protected]

  •  Accepted: 30 April 2011
  •  Published: 30 May 2011



The bacteriocins produced by Enterococcus species (enterocins) show considerable activity against diverse pathogens. One of these antimicrobial peptides was isolated fromEnterococcus faecium E86 cultured in MRS broth for 24 h at 37°C. The antimicrobial peptide was purified by precipitation in 75% ammonium sulfate, followed by chloroform precipitation and chromatography in Dowex-50, resulting in a specific activity of 52.46 AU/ mg in a final yield of 80% and a 6-fold recovery. The enterocin was purified to homogeneity and had an apparent molecular mass of 3.5 kDa as evaluated by 18% SDS-PAGE. The purified and the partial-purified enterocin were able to inhibit the proliferation of natural microbiota of fresh-cut lettuce as well as that artificially contaminated with Listeria spp. After 30 min in the presence of 0.5% acetic acid, the natural microbiota proliferation was reduced by 3 log cycles, while the enterocin in its purified or partially purified form showed an inhibition of the microbiota proliferation by 1 or 2 log cycles, respectively. These results indicate that enterocin could be used as a natural antimicrobial to reduce chemical treatment in minimally processed leafy vegetables.


Key words: Bacterial enzymes, antimicrobial peptide, purification and characterization of enzymes, food safety.