Production of the antimicrobial peptides Caseicin A and B by Bacillus isolates growing on sodium caseinate

Lett Appl Microbiol. 2012 Aug;55(2):141-8. doi: 10.1111/j.1472-765X.2012.03271.x. Epub 2012 Jul 10.

Abstract

Aims: The aim of this study was to identify Bacillus isolates capable of degrading sodium caseinate and subsequently to generate bioactive peptides with antimicrobial activity.

Methods and results: Sodium caseinate (2.5% w/v) was inoculated separately with 16 Bacillus isolates and allowed to ferment overnight. Protein breakdown in the fermentates was analysed using gel permeation-HPLC (GP-HPLC) and screened for peptides (<3-kDa) with MALDI-TOF mass spectrometry. Caseicin A (IKHQGLPQE) and caseicin B (VLNENLLR), two previously characterized antimicrobial peptides, were identified in the fermentates of both Bacillus cereus and Bacillus thuringiensis isolates. The caseicin peptides were subsequently purified by RP-HPLC and antimicrobial assays indicated that the peptides maintained the previously identified inhibitory activity against the infant formula pathogen Cronobacter sakazakii.

Conclusions: We report a new method using Bacillus sp. to generate two previously characterized antimicrobial peptides from casein.

Significance and impact of the study: This study highlights the potential to exploit Bacillus sp. or the enzymes they produce for the generation of bioactive antimicrobial peptides from bovine casein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimicrobial Cationic Peptides / metabolism*
  • Antimicrobial Cationic Peptides / pharmacology
  • Bacillus / isolation & purification
  • Bacillus / metabolism*
  • Caseins / metabolism*
  • Cattle
  • Chromatography, High Pressure Liquid / methods
  • Cronobacter sakazakii / drug effects
  • Microbial Sensitivity Tests
  • Peptide Fragments / metabolism*

Substances

  • Antimicrobial Cationic Peptides
  • Caseins
  • Peptide Fragments
  • caseicin A
  • caseicin B