Isolation and partial characterization of bacteriocins from<Emphasis Type="Italic"> Pediococcus</Emphasis> species

Lactic acid bacteria have received increased attention as a potential food preservative due to their strong antagonistic activity against many food-spoilage and pathogenic organisms. Three Pediococcus species, P. acidilactici NCIM 2292, P. pentosaceous. NCIM 2296 and P. cervisiae NCIM 2171, were evaluated for bacteriocin production. Inhibitory substance were produced during the late growth phase and maximum production occurred at 37 °C after 36–48 h of incubation. Bacteriocins partially purified from these species by cold-acetone precipitation at 0 °C and cell adsorption desorption techniques have a broad inhibitory spectrum against microorganisms, including gram-negative bacteria such as Escherichia coli and Pseudomonas. Proteolytic enzymes inactivated these peptides, but amylase and lipase did not show any effect. The bacteriocins were stable over a wide pH range (3–8) and apparently most active at pH 4.0–5.0. They were heat-stable (1 h at ~80 °C and autoclaving) at pH 5.0. No loss in activity was observed when stored under refrigeration (4–8 °C). Tris-Tricine SDS-PAGE revealed the molecular masses of these peptides to be between 3.5 and 5.0 kDa.