Purification and characterization of the bacteriocin produced by L actobacillus sakei MBS a1 isolated from B razilian salami

Aims The study aimed at determining the biochemical characteristics of the bacteriocin produced by L actobacillus sakei MBS a1, isolated from salami, correlating the results with the genetic features of the producer strain. Methods and Results Identification of strain MBS a1 was performed by 16 S rDNA sequencing. The bacteriocin was tested for spectrum of activity, heat and p H stability, mechanism of action, molecular mass and amino acid sequence when purified by cation‐exchange and reversed‐phase HPLC . Genomic DNA was tested for bacteriocin genes commonly present in L act. sakei . Bacteriocin MBS a1 was heat‐stable, unaffected by pH 2·0 to 6·0 and active against all tested L isteria monocytogenes strains. Maximal production of bacteriocin MBS a1 (1600 AU ml −1 ) in MRS broth occurred after 20 h at 25°C. The molecular mass of produced bacteriocin was 4303·3 Da, and the molecule contained the SIIGGMISGWAASGLAG sequence, also present in sakacin A . The strain contained the sakacin A and curvacin A genes but was negative for other tested sakacin genes (sakacins T‐ α , T‐ β , X, P, G and Q). Conclusions In the studied conditions, L act. sakei MBS a1 produced sakacin A , a class II bacteriocin, with anti‐ L isteria activity. Significance and Impact of the Study The study covers the purification and characterization of the bacteriocin produced by a lactic acid bacteria isolated from salami ( L act. sakei MBS a1), linking genetic and expression information. Its heat‐resistance, p H stability in acid conditions (p H 2·0–6·0) and activity against L . monocytogenes food isolates bring up a potential technological application to improve food safety.