title: An extracellular polymer at the interface of magnetic bioseparations.
abstract: FucoPol, a fucose-containing extracellular polysaccharide (EPS) produced by bacterium Enterobacter A47 using glycerol as the carbon source, was employed as a coating material for magnetic particles (MPs), which were subsequently functionalized with an artificial ligand for the capture of antibodies. The performance of the modified MPs (MP-EPS-22/8) for antibody purification was investigated using direct magnetic separation alone or combined with an aqueous two-phase system (ATPS) composed of polyethylene glycol (PEG) and dextran. In direct magnetic capturing, and using pure protein solutions of human immunoglobulin G (hIgG) and bovine serum albumin (BSA), MP-EPS-22/8 bound 120 mg hIgG g(-1) MPs, whereas with BSA only 10 ± 2 mg BSA g(-1) MPs was achieved. The hybrid process combining both the ATPS and magnetic capturing leads to a good performance for partitioning of hIgG in the desired phase as well as recovery by the magnetic separator. The MPs were able to bind 145 mg of hIgG g(-1) of particles which is quite high when compared with direct magnetic separation. The theoretical maximum capacity was calculated to be 410 ± 15 mg hIgG adsorbed g(-1) MPs with a binding affinity constant of 4.3 × 10(4) M(-1). In multiple extraction steps, the MPs bound 92% of loaded hIgG with a final purity level of 98.5%. The MPs could easily be regenerated, recycled and re-used for five cycles with only minor loss of capacity. FucoPol coating allowed both electrostatic and hydrophobic interactions with the antibody contributing to enhance the specificity for the targeted products.
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Vijaykumar L
authors.initials: VL
authors.lastname: Dhadge
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Patricia I
authors.initials: PI
authors.lastname: Morgado
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Filomena
authors.initials: F
authors.lastname: Freitas
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Reis
authors.affiliation: Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Azevedo
authors.affiliation: Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
authors.forename: Raquel
authors.initials: R
authors.lastname: Aires-Barros
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal cecilia.roque@fct.unl.pt.
authors.forename: A Cecilia A
authors.initials: AC
authors.lastname: Roque
mesh_terms: D000818:Animals; D002417:Cattle; D003451:Cryoprotective Agents / Q000494:pharmacology; D004754:Enterobacter / Q000254:growth & development; D005990:Glycerol / Q000494:pharmacology; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007074:Immunoglobulin G / Q000737:chemistry / Q000302:isolation & purification*; D008280:Magnetics; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000302:isolation & purification*; D055672:Static Electricity
chemical_list: D003451:Cryoprotective Agents; D007074:Immunoglobulin G; D011135:Polysaccharides, Bacterial; D012710:Serum Albumin, Bovine; D005990:Glycerol
keywords: aqueous two-phase extraction; bacterial extracellular polysaccharide; human antibodies; magnetic particles; magnetic separation; synthetic affinity ligand