Purification of bacteriocins by chromatographic methods

Abstract

The bacteriocins secreted by the cells of two B. subtilis strains have been isolated by hydrophobic or ion-exchange chromatography on CMC followed by purification on membranes. The yields of electrophoretically pure products were ~75 % of the total activity in the supernatant of culture fluid obtained after cell sedimentation. The bacteriocin secreted by B. subtilis BSX strain cells has high hydrophobicity, and it is mainly found on the surface of cell walls in the culture fluid. These fragments served as sorbents in hydrophobic chromatography. A B. subtilis strain B-112 bacteriocin predominantly occurs in the free state in the culture fluid supernatant. It was purified after the removal of cell debris on CMC and was then eluted with a glycine-HCl buffer at pH 2.5. The concentration of the purified bacteriocins was determined at 205 nm; therefore, the method did not require aromatic amino acids to be available in the macromolecule structure. It is believed that these chromatographic techniques can be used for purification with a high yield of bacteriocins of other producers.