African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5224

Full Length Research Paper

New insight into the regulation of classâ…¡ bacteriocin production by quorum sensing in Lactobacillus pentosus 31-1

Xiangmei Zhang1,2, Guorong Liu1, Bin Zhao1 and Pinglan Li 1*
1College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China. 2College of Biological Science and Engineering, Hebei University of Economics and Business, Shijiazhuang, 050061, China.
Email: [email protected]

  •  Accepted: 25 January 2012
  •  Published: 23 April 2012

Abstract

The biosynthesis of class II bacteriocins is frequently regulated by a quorum-sensing regulatory mechanism meditated by autoinducing peptide. Here, it was preliminarily confirmed that bacteriocin production by Lactobacillus pentosus 31-1 was controlled by a quorum sensing (QS) system meditated by peptide signal molecules in the cell-free supernatant (CFS). Effects of the growth medium and inoculums size on bacteriocin producing in L. pentosus 31-1 were investigated. Bacteriocin production could be detected even when L. pentosus 31-1 was diluted 108-fold in MRS broth and incubated at 37°C for 24 h. However, by dilution of the culture 200-fold or more in skim milk medium, no bacteriocin activity could be detected after 60 h of incubation. Bacteriocin production could be switched on in these cultures after the addition of CFS from a bacteriocin-producing culture, and the active components in the CFS were shown to be peptides in nature. FII-22, one of the fractions purified from the CFS was identified as the putative inducing peptide (IP). Regulation of bacteriocin production in L. pentosus 31-1 by FII-22 was affected by the additional time and amount. The optimal induction of bacteriocin production effect was obtained by addition of 0.5 µg/ml (final concentration) FII-22 to the culture after 8 h of incubation. This study provided a novel perspective on screening for QS regulated class II bacteriocin producing lactic acid bacteria. This study may assist in a deeper understanding of how QS works on regulation of class II bacteriocin production.

 

Key words: Quorum sensing, class II bacteriocin, Lactobacillus pentosus, inducing peptide, skim milk medium.