title: Decrease of U(VI) immobilization capability of the facultative anaerobic strain Paenibacillus sp. JG-TB8 under anoxic conditions due to strongly reduced phosphatase activity.
abstract: Interactions of a facultative anaerobic bacterial isolate named Paenibacillus sp. JG-TB8 with U(VI) were studied under oxic and anoxic conditions in order to assess the influence of the oxygen-dependent cell metabolism on microbial uranium mobilization and immobilization. We demonstrated that aerobically and anaerobically grown cells of Paenibacillus sp. JG-TB8 accumulate uranium from aqueous solutions under acidic conditions (pH 2 to 6), under oxic and anoxic conditions. A combination of spectroscopic and microscopic methods revealed that the speciation of U(VI) associated with the cells of the strain depend on the pH as well as on the aeration conditions. At pH 2 and pH 3, uranium was exclusively bound by organic phosphate groups provided by cellular components, independently on the aeration conditions. At higher pH values, a part (pH 4.5) or the total amount (pH 6) of the dissolved uranium was precipitated under oxic conditions in a meta-autunite-like uranyl phosphate mineral phase without supplying an additional organic phosphate substrate. In contrast to that, under anoxic conditions no mineral formation was observed at pH 4.5 and pH 6, which was clearly assigned to decreased orthophosphate release by the cells. This in turn was caused by a suppression of the indigenous phosphatase activity of the strain. The results demonstrate that changes in the metabolism of facultative anaerobic microorganisms caused by the presence or absence of oxygen can decisively influence U(VI) biomineralization.
authors.affiliation: Helmholtz-Center Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany; Helmholtz-Center for Environmental Research, Department of Soil Ecology, Halle, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Reitz
authors.affiliation: Helmholtz-Center Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany.
authors.forename: Andre
authors.initials: A
authors.lastname: Rossberg
authors.affiliation: Helmholtz-Center Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Barkleit
authors.affiliation: Helmholtz-Center Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Selenska-Pobell
authors.affiliation: University of Granada, Department of Microbiology, Granada, Spain.
authors.forename: Mohamed L
authors.initials: ML
authors.lastname: Merroun
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D010100:Oxygen / Q000378:metabolism*; D056507:Paenibacillus / Q000166:cytology / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D014501:Uranium / Q000378:metabolism*; D017974:Uranium Compounds / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010710:Phosphates; D017974:Uranium Compounds; C075963:hydrogen uranyl phosphate; D014501:Uranium; D010744:Phosphoric Monoester Hydrolases; D010100:Oxygen