The partial characterization of the antibacterial peptide bacteriocin G(2) produced by the probiotic bacteria Lactobacillus plantarum G(2)

The aim of this study was the partial characterization of the antimicrobial peptide bacteriocin G, produced by probiotic bacteria Lactobacillus plantarum G(2), which was isolated from a clinical sample of a healthy person. Antimicrobial substance was secreted in the supernatant of an L. plantarum G(2) culture, and showed a diverse spectrum of antimicrobial activity of all the tested strains of the genera Lactobacillus and the pathogenic bacteria Staphylococcus aureus and Salmonella abony. Isoclectric focusing revealed that bacteriocin G(2) is a cationic peptide (pI about 10) with a molecular mass of 2.2 kDa according to tricine sodium dodecyl sulphate polyacrylamide gel electrophoresis, SDS-PAGE. The antimicrobial activity of bactcriocin G(2) was diminished by the proteolytic action of trypsin and proteinase K. Bacteriocin G(2) preserved its biological activity in the temperature range 40-60 degrees C (15 min), which was lost at 80 degrees C. Bacteriocin G(2) was stable in the pH range 2-9, while treatment with 1 % Tween 80 and 1 % urea resulted in increased antimicrobial activity. The probiotic strain L. plantarum G(2) produces the antimicrobial substance proteinaceous in nature with bacteriocin characteristics. Bacteriocin production is one of the key properties of probiotic bacteria with clinical potential as anti-infective agents, which will increase the likelihood of its in vivo efficacy.