Antibacterial efficacy of lactic acid bacteria and bacteriocin isolated from Dadih’s against Staphylococcus aureus

Bacteriocin, a peptide produced by lactic acid bacteria (LAB) widely used as a natural and safe preservative in food products. This work aimed to evaluate the characterization of bacteriocin from dadih’s LAB and to study its antimicrobial activity against Staphylococcus aureus. Supernatant from 12 LBA strains could inhibit S. aureus growth with different inhibition zones. Only nine strains showed inhibition zones of > 3.5 mm and were further evaluated for their antibacterial compounds. Three strains had antimicrobial activity derived from organic acids, especially lactic acid, and six strains had antimicrobial compounds in the form of bacteriocin. Bacteriocin strain R-55 showed the highest activity against S. aureus, with an average inhibition zone of 8.43 mm. The molecular weight of the purified isolated bacteriocin from the R-55 strain was 14.4 kDa. Bacteriocin obtained from St. faecalis subsp. liquefaciens R-55 is a promising natural preservative to prevent the growth of S. aureus as foodborne pathogens.