title: Biological ferrous sulfate oxidation by A. ferrooxidans immobilized on chitosan beads.
abstract: The immobilization of Acidithiobacillus ferrooxidans cells on chitosan and cross-linked chitosan beads and the biooxidation of ferrous iron to ferric iron in a packed-bed bioreactor were studied. The biofilm formation was carried out by using a glass column reactor loaded with chitosan or cross-linked chitosan beads and 9 K medium previously inoculated with A. ferrooxidans cells. The immobilization cycles on the carrier matrix with the bioreactor operating in batch mode were compared. Then, the reactor was operated using a continuous flow of 9 K medium at different dilution rates. The results indicate that the packed-bed reactor allowed increasing the flow rate of medium approximately two fold (chitosan) and eight fold (chitosan cross-linked) without cells washout, compared to a free cell suspension reactor used as control, and to reach ferric iron productivities as high as 1100 and 1500 mg l(-1) h(-1) respectively. Scanning electron microscopy micrographs of the beads, infrared spectroscopy and the X-ray diffraction patterns of precipitates on the chitosan beads were also investigated.
authors.affiliation: Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, (8300) Neuquén, Argentina. agiaveno@uncoma.edu.ar
authors.forename: A
authors.initials: A
authors.lastname: Giaveno
authors.forename: L
authors.initials: L
authors.lastname: Lavalle
authors.forename: E
authors.initials: E
authors.lastname: Guibal
authors.forename: E
authors.initials: E
authors.lastname: Donati
mesh_terms: D042763:Acidithiobacillus / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D018441:Biofilms / Q000254:growth & development; D019149:Bioreactors; D018914:Cells, Immobilized / Q000378:metabolism*; D048271:Chitosan / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism; D005296:Ferrous Compounds / Q000737:chemistry / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010084:Oxidation-Reduction; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; C020748:ferrous sulfate; C024823:ferric sulfate; D048271:Chitosan