Characterization and purification of bacteriocin produced by Enterococcus sp. GHB26 isolated from Algerian paste of dates Ghars

Strain Enterococcus sp. GHB26, isolated from the Algerian paste of dates "Ghars", produced a bacteriocin. This bacteriocin was inactivated by proteolytic enzymes. Antibacterial activity of the bacteriocin was heat stable at 120°C for 20 min (533 AU/ml), stable at pH range of 2 to 12 and resistant to chemicals (SDS, EDTA, NaCl, Tween 80, Urea). The active bacteriocin from the cell-free supernatant of Enterococcus sp. GHB26 was purified by precipitation with ammonium sulfate followed by various combinations of gel filtration on a Sephadex G-25 column, cation exchange chromatography on a CM- Sephadex Cellulose column and reverse phase-high performance liquid chromatography on a C18 column. The bacteriocin was eluted as a single peak on the chromatogram from reverse phase-high performance liquid chromatography attesting the purity of this bacteriocin. The bacteriocin exhibited a bactericidal mode of action. Sodium dodecyl sulphate - polyacrylamide gel electrophoresis indicated that molecular weight of this bacteriocin is close to 3.5 kDa.