Bacteriocinogenic activity from starter cultures used in Spanish meat industry.

Thirty-nine bacterial strains, obtained from commercial starter cultures and commonly used by the meat industry in Spain, have been examined for their ability to produce bacteriocins. Fourteen (35%) of them showed antagonism against at least one of the indicator strains, by the agar spot test. The strains showing an inhibitory action against pathogenic indicator strains were identified as Pediococcus acidilactici, Lactobacillus curvatus, Lactobacillus pentosus and Lactobacillus plantarum, which showed an inhibitory action against a wide range of Gram-positive bacteria. The only strain which showed reliable inhibitory activity against pathogenic indicator strains, by the well diffusion assay, was P. acidilactici. This strain produces an inhibitory compound, which reaches its maximum activity at the beginning of the stationary phase of growth. This antimicrobial substance (bacteriocin) has a proteinaceous nature, is stable over a broad range of pH, resistant to heat and shows a bactericidal action.

Purification and amino acid sequence of a bacteriocin produced by Pediococcus acidilactici.

A bacteriocin produced by Pediococcus acidilactici has been purified to homogeneity by a rapid and simple four-step purification procedure which includes ammonium sulphate precipitation, chromatography with a cation-exchanger and Octyl Sepharose, and reverse-phase chromatography. The purification resulted in an approximately 80,000-fold increase in the specific activity and about a 6-fold increase in the total activity. The amino acid composition and sequencing data indicated that the bacteriocin contained 43-44 amino acid residues. The predicted M(r) and isolectric point of the bacteriocin are about 4600 and 8.6, respectively. Comparing the amino acid sequence of this bacteriocin with the sequences of leucocin A-UAL 187, sakacin P and curvacin A (bacteriocins produced by Leuconostoc gelidum, Lactobacillus sake and Lactobacillus curvatus, respectively) revealed that all four bacteriocins had in their N-terminal region the sequence Tyr-Gly-Asn-Gly-Val-Xaa-Cys, indicating that this concensus sequence is of fundamental importance for this group of bacteriocins. The bacteriocin from P. acidilactici and sakacin P were very similar, having at least 25 common amino acid residues. The sequence similarity was greatest in the N-terminal half of the molecules--17 of the first 19 residues were common--indicating the fundamental importance of this region. Leucocin A-UAL 187 and curvacin A had, respectively, at least 16 and 13 amino acid residues in common with the bacteriocin from P. acidilactici.