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

Abstract

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.