title: Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria.
abstract: Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery.
authors: Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany. James.Byrne@uni-tuebingen.de.
authors: James M
authors: JM
authors: Byrne
authors: Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany.
authors: Nicole
authors: N
authors: Klueglein
authors: School of Chemistry, University of Manchester, M13 9PL Manchester, UK. Pacific Northwest National Laboratory, Richland, WA 99352, USA.
authors: Carolyn
authors: C
authors: Pearce
authors: Pacific Northwest National Laboratory, Richland, WA 99352, USA.
authors: Kevin M
authors: KM
authors: Rosso
authors: Geophysics, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany.
authors: Erwin
authors: E
authors: Appel
authors: Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany.
authors: Andreas
authors: A
authors: Kappler
mesh_terms: D018920:Coculture Techniques; D004583:Electrons; D052203:Ferrosoferric Oxide / Q000378:metabolism*; D045302:Geobacter / Q000254:growth & development / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008027:Light; D058185:Magnetite Nanoparticles; D010084:Oxidation-Reduction; D012241:Rhodopseudomonas / Q000254:growth & development / Q000378:metabolism*
chemical_list: D058185:Magnetite Nanoparticles; D007501:Iron; D052203:Ferrosoferric Oxide