Isolation, characterization, and antimicrobial evaluation of bacteriocin produced by lactic acid bacteria against Erwinia carotovora

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.

Keywords:
lactic acid bacteria; Erwinia carotovora; bacteriocin; bio-preservative; antimicrobial activity