title: Expanded bed adsorption as a unique unit operation for the isolation of bacteriocins from fermentation media.
abstract: Expanded bed adsorption using a strong cation exchanger allowed the direct isolation of amylovorin L471, a bacteriocin from Lactobacillus amylovorus DCE 471, from the fermentation medium. The pH of the loading and elution buffer were optimised in a packed bed with cell-free culture supernatant. Bound bacteriocin was eluted with 1.0 M NaCl. The highest recovery (30%) was obtained at the lowest pH (3.6). At higher pH values the recovery was lower, namely 12%, 15% and 7% at pH 4.5, 6.5 and 8.0, respectively. In expanded bed mode, direct isolation of the bacteriocin from the fermentation medium at pH 3.6 (loading and elution) initially resulted in a recovery of 12%. After optimisation of the pH (loading and elution at pH 3.6 and 6.5, respectively), the recovery for amylovorin L471 increased up to 30% and higher. Recovery of enterocin A from Enterococcus faecium CTC 492 fermentation medium averaged 15% (loading and elution at pH 3.6 and 6.0, respectively). With pediocin, produced by Pediococcus acidilactici ATCC 8042, 26% recovery was obtained at a pH of 6.5 during loading and elution. Low recoveries can be ascribed to non-optimal operation conditions (pH of loading and elution buffer), inactivation of the bacteriocin on a cationic resin, and the formation of more insoluble and less active, strongly hydrophobic bacteriocin aggregates upon further purification.
authors.affiliation: Department of Biotechnology, Faculty of Sciences, Vrije Universiteit Brussel (VUB), Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Callewaert
authors.forename: L
authors.initials: L
authors.lastname: De Vuyst
mesh_terms: D000327:Adsorption; D001430:Bacteriocins / Q000302:isolation & purification*; D002474:Cell-Free System; D003470:Culture Media / Q000737:chemistry*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration
chemical_list: D001430:Bacteriocins; D003470:Culture Media; C402567:amylovorin L471