Journal of
Microbiology and Antimicrobials

  • Abbreviation: J. Microbiol. Antimicrob.
  • Language: English
  • ISSN: 2141-2308
  • DOI: 10.5897/JMA
  • Start Year: 2009
  • Published Articles: 157

Full Length Research Paper

Purification and characterization of a bacteriocin produced by Lactococcus lactis subsp. lactis PD6.9

Margarete Alice Fontes Saraiva*
  • Margarete Alice Fontes Saraiva*
  • Departamento de Microbiologia, Universidade Federal de Viçosa, 36570000, Viçosa, Minas Gerais, Brazil.
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Ingolf Figved Nes
  • Ingolf Figved Nes
  • Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO Box 5003, 1432, Aas, Norway.
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Maria Cristina Baracat-Pereira
  • Maria Cristina Baracat-Pereira
  • Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, 36570000, Viçosa, Minas Gerais, Brazil.
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Marisa Vieira de Queiroz
  • Marisa Vieira de Queiroz
  • Departamento de Microbiologia, Universidade Federal de Viçosa, 36570000, Viçosa, Minas Gerais, Brazil.
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Hilário Cuquetto Mantovani
  • Hilário Cuquetto Mantovani
  • Departamento de Microbiologia, Universidade Federal de Viçosa, 36570000, Viçosa, Minas Gerais, Brazil.
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Célia Alencar de Moraes
  • Célia Alencar de Moraes
  • Departamento de Microbiologia, Universidade Federal de Viçosa, 36570000, Viçosa, Minas Gerais, Brazil.
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  •  Received: 04 February 2014
  •  Accepted: 24 June 2014
  •  Published: 31 July 2014

Abstract

In this study, a bacteriocin produced by Lactococcus lactis subsp. lactis PD6.9 was purified, characterized and identified. The bacteriocin was purified to homogeneity from culture supernatant by cation exchange and reversed-phase liquid chromatography, and its molecular weight was determined by mass spectrometry. The presence of the nisin gene was confirmed by polymerase chain reaction (PCR) and DNA sequencing. The gene showed that it was a natural nisin variant, nisin Z, as indicated by substitution of an asparagine residue for histidine at position 27. The purified bacteriocin was biochemically pure, and the molecular weight was approximately 3329.571 Da. The peak of nisin Z production by L. lactis PD6.9 occurred after 5 h of culture during stationary phase. This bacteriocin demonstrated inhibitory activity towards significant foodborne pathogens and Staphylococcus aureus strains isolated from dairy cattle diagnosed with mastitis, it may be useful for future applications.

 

Key words: Antimicrobials, Lactococcus lactis, bacteriocins, identification, inhibitory activity.