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

• Published in: Letters in applied microbiology Vol. 55; no. 2; pp. 141 - 148
• Main Authors: Kent, R.M, Guinane, C.M, O’Connor, P.M, Fitzgerald, G.F, Hill, C, Stanton, C, Ross, R.P
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.08.2012; Blackwell
• Subjects: Animals; Antimicrobial Cationic Peptides - metabolism; Antimicrobial Cationic Peptides - pharmacology; antimicrobial peptides; antimicrobial properties; Bacillus; Bacillus - isolation & purification; Bacillus - metabolism; Bacillus cereus; Bacillus thuringiensis; bioactives; Biological and medical sciences; casein; Caseins - metabolism; Cattle; Chromatography, High Pressure Liquid - methods; Cronobacter sakazakii; Cronobacter sakazakii - drug effects; enzymes; Fundamental and applied biological sciences. Psychology; gels; infant formulas; mass spectrometry; Microbial Sensitivity Tests; Microbiology; new methods; pathogens; Peptide Fragments - metabolism; sodium caseinate; Bacillales; Peptides; Sodium; bioactives; Applied microbiology; Bacillus; Production; Bacteria; Isolate; Bacillaceae; Antimicrobial agent; antimicrobial peptides
• ISSN: 0266-8254; 1472-765X
• DOI: 10.1111/j.1472-765X.2012.03271.x

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.