Partial characterization of a class IIa pediocin produced by Pediococcus parvulus 133 strain isolated from meat (Mexican “chorizo”)

Abstract

Pediocin-like bacteriocins are antimicrobial substances produced by some bacteria with high antilisterial activity. Several isolates of Pediococcus acidilactici and two Pediococcus parvulus strains of vegetable origin have been reported to produce this kind of peptide. This work presents the partial characterization of the bacteriocin produced by P. parvulus 133 found in meat and confirms its identity as a heat resistant, antilisterial bacteriocin. This peptide has a relatively narrow inhibitory spectrum but a high antilisterial activity. Pediocin remained active after heating to 121 °C, but its thermoresistance varied with pH. The pH selective adsorption method resulted in a 150-fold concentration of antimicrobial activity. The final extract was obtained by ultrafiltration and resulted in an additional 10-fold concentration of activity. Molecular weight was estimated as 5 kDa and isoelectric point was 8.65. The sequence of the first 17 aminoacids at the N-terminal end of the bacteriocin showed complete coincidence with that previously reported for pediocin A1 (AcH) and with an antilisterial peptide produced by Bacillus coagulans. High sequence similarity was also found with two other antilisterial bacteriocins.