Abstract 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.

Abstract This study aimed to estimate the antimicrobial efficiency and stability of the crude bacteriocin produced by dadih’s LAB against Erwinia carotovora under different pH, temperature, and enzymatic treatments. Twelve strains of LAB were isolated from the dadih including four strains were Leuconostoc sp. and eight were Streptococcus sp. The antimicrobial effects of bacteriocins from the genus Streptococcus sp. against Erwinia carotovora were higher than the genus Leuconostoc sp. The isolated bacteriocins showed potential stability indifferent pH (3 to 11) and temperature conditions (30 to 121 ◦C). Six of nine bacteriocins included Enterococcus faecalis subsp. liquefaciens R-19, R-55, R-32, Streptococcus lactis subsp. diacetylactis R-41, R-43, and Leuconostoc paramesenteroides R-45 induced the highest stability under different temperatures and pH. Analysis of the 16s rDNA of isolates R-43 and R-55 showed that these bacteria belong to Enterococcus hirae and Pediococcus pentosaceous, respectively. The treatment with amylase, proteinase K, and trypsin revealed that R-43 and R-55 probably belong to the group IIa classification of bacteriocins (Antilisteria-Pediocin-like bacteriocins). It could be concluded that dadih’s LAB is a promising source for bacteriocins used safely in the bio-preservatives of the food products under different storage conditions.