Production of the antimicrobial peptides Caseicin A and B by Bacillus isolates growing on sodium caseinate.
OBJECTIVE
The aim of this study was to identify Bacillus isolates capable of degrading sodium caseinate and subsequently to generate bioactive peptides with antimicrobial activity.


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.


CONCLUSIONS
This study highlights the potential to exploit Bacillus sp. or the enzymes they produce for the generation of bioactive antimicrobial peptides from bovine casein.
Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland.
R M
RM
Kent
C M
CM
Guinane
P M
PM
O'Connor
G F
GF
Fitzgerald
C
C
Hill
C
C
Stanton
R P
RP
Ross
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism* / Q000494:pharmacology; D001407:Bacillus / Q000302:isolation & purification / Q000378:metabolism*; D002364:Caseins / Q000378:metabolism*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D044083:Cronobacter sakazakii / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010446:Peptide Fragments / Q000378:metabolism*
D023181:Antimicrobial Cationic Peptides; D002364:Caseins; D010446:Peptide Fragments; C572873:caseicin A; C572875:caseicin B