Partial characterization of bacteriocin-like peptide produced by lactobacillus acidophilus DSM 20079

Abstract EN

Antagonistic effect of some strains of lactic acid bacteria and bifid bacteria were studied.

Lactobacillus acidophilus DSM 20079 produced bacteriocin-like activity against different bacteria including some pathogenic and food-spoilage species.

The strain produced antibacterial peptide after 2 hours, and the level of the peptide was at a maximum after 30 hr during fermentation.

The peptide exhibited antibacterial activity against Lactobacillus delbrueckii ssp bulgaricus DSM 20081, Bacillus subtilis, Bacillus series, Escherichia Coli, Enterococcus faecalis and Salmonella typhimurium but not against staphylococcus aureus, Lactobacillus acidophilus DSM 9126, Lactobacillus acidophilus DSM 20242, Lactobacillus delbrueckii ssp bulgaricus DSM 20080 Streptococcus thermophiles DSM 20617, bifid bacterium infantis DSM 20088 and Bifid bacterium angulate DSM 20097.

The bacteriocin-like peptide completely lost its activity by proteolysis hydrolysis with pepsin, trypsin and chemo trypsin.

However, the antibacterial activity of the peptide was well maintained at pH between 2.0 and 9.0.

The activity remained after heat treatment at 50-140oC for 5-15 min.

Most of bacteriocin-like peptide precipitated with 40-50% ammonium sulfate saturation.

Growth rate of Lactobacillus delbrueckii ssp bulgaricus in MRS completely inhibited with addition of different levels of cell-free supernatant from Lactobacillus acidophilus DSM 20079 as measured at 620 nm.

The molecular mass of the bacteriocin-like peptide was found to be 33 kDa.