title: Multistage bioassociation of uranium onto an extremely halophilic archaeon revealed by a unique combination of spectroscopic and microscopic techniques.
abstract: The interactions of two extremely halophilic archaea with uranium were investigated at high ionic strength as a function of time, pH and uranium concentration. Halobacterium noricense DSM-15987 and Halobacterium sp. putatively noricense, isolated from the Waste Isolation Pilot Plant repository, were used for these investigations. The kinetics of U(VI) bioassociation with both strains showed an atypical multistage behavior, meaning that after an initial phase of U(VI) sorption, an unexpected interim period of U(VI) release was observed, followed by a slow reassociation of uranium with the cells. By applying in situ attenuated total reflection Fourier-transform infrared spectroscopy, the involvement of phosphoryl and carboxylate groups in U(VI) complexation during the first biosorption phase was shown. Differences in cell morphology and uranium localization become visible at different stages of the bioassociation process, as shown with scanning electron microscopy in combination with energy dispersive X-ray spectroscopy. Our results demonstrate for the first time that association of uranium with the extremely halophilic archaeon is a multistage process, beginning with sorption and followed by another process, probably biomineralization.
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors.forename: Miriam
authors.initials: M
authors.lastname: Bader
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Müller
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Foerstendorf
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Drobot
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Helmholtz Centre for Environmental Research-UFZ, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig, Germany.
authors.forename: Niculina
authors.initials: N
authors.lastname: Musat
authors.affiliation: Los Alamos National Laboratory, Repository Science and Operations, 1400 University Drive, Carlsbad, NM, 88220, USA.
authors.forename: Juliet S
authors.initials: JS
authors.lastname: Swanson
authors.affiliation: Los Alamos National Laboratory, Repository Science and Operations, 1400 University Drive, Carlsbad, NM, 88220, USA.
authors.forename: Donald T
authors.initials: DT
authors.lastname: Reed
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Stumpf
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany. Electronic address: a.cherkouk@hzdr.de.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cherkouk
mesh_terms: D001105:Archaea / Q000737:chemistry / Q000378:metabolism*; D006217:Halobacterium / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008853:Microscopy; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D011850:Radioactive Waste / Q000032:analysis*; D054712:Salinity; D013050:Spectrometry, Fluorescence; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D014501:Uranium / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D011850:Radioactive Waste; D014501:Uranium
keywords: Final disposal of radioactive waste; Halophilic archaeon Halobacterium noricense; In situ ATR FT-IR spectroscopy; Luminescence spectroscopy at high salinity; Uranium bioassociation