title: Identification of Mn(II)-oxidizing bacteria from a low-pH contaminated former uranium mine.
abstract: Biological Mn oxidation is responsible for producing highly reactive and abundant Mn oxide phases in the environment that can mitigate metal contamination. However, little is known about Mn oxidation in low-pH environments, where metal contamination often is a problem as the result of mining activities. We isolated two Mn(II)-oxidizing bacteria (MOB) at pH 5.5 (Duganella isolate AB_14 and Albidiferax isolate TB-2) and nine strains at pH 7 from a former uranium mining site. Isolate TB-2 may contribute to Mn oxidation in the acidic Mn-rich subsoil, as a closely related clone represented 16% of the total community. All isolates oxidized Mn over a small pH range, and isolates from low-pH samples only oxidized Mn below pH 6. Two strains with different pH optima differed in their Fe requirements for Mn oxidation, suggesting that Mn oxidation by the strain found at neutral pH was linked to Fe oxidation. Isolates tolerated Ni, Cu, and Cd and produced Mn oxides with similarities to todorokite and birnessite, with the latter being present in subsurface layers where metal enrichment was associated with Mn oxides. This demonstrates that MOB can be involved in the formation of biogenic Mn oxides in both moderately acidic and neutral pH environments.
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany U.S. Geological Survey, National Research Program, Reston, Virginia, USA dakob@usgs.gov.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Akob
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Tsing
authors.initials: T
authors.lastname: Bohu
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Beyer
authors.affiliation: Institute of Geosciences, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Schäffner
authors.affiliation: Institute of Geosciences, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Händel
authors.affiliation: Department of Geosciences, Virginia Tech, Blacksburg, Virginia, USA.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Johnson
authors.affiliation: Institute of Geosciences, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Merten
authors.affiliation: Institute of Geosciences, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Büchel
authors.affiliation: Institute of Geosciences, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Kai Uwe
authors.initials: KU
authors.lastname: Totsche
authors.affiliation: Institute of Ecology, Friedrich Schiller University Jena, Jena, Germany German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig, Leipzig, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Küsel
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000378:metabolism*; D008906:Mining; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014501:Uranium / Q000378:metabolism*
chemical_list: D017895:Manganese Compounds; D012987:Soil; D014501:Uranium