title: Fate of selenate and selenite metabolized by Rhodobacter sphaeroides.
abstract: Cultures of a purple nonsulfur bacterium, Rhodobacter sphaeroides, amended with approximately 1 or approximately 100 ppm selenate or selenite, were grown phototrophically to stationary phase. Analyses of culture headspace, separated cells, and filtered culture supernatant were carried out using gas chromatography, X-ray absorption spectroscopy, and inductively coupled plasma spectroscopy-mass spectrometry, respectively. While selenium-amended cultures showed much higher amounts of SeO(3)(2-) bioconversion than did analogous selenate experiments (94% uptake for SeO(3)(2-) as compared to 9.6% for SeO(4)(2-)-amended cultures from 100-ppm solutions), the chemical forms of selenium in the microbial cells were not very different except at exposure to high concentrations of selenite. Volatilization accounted for only a very small portion of the accumulated selenium; most was present in organic forms and the red elemental form.
authors.affiliation: Chemistry Department and Texas Research Institute for Environmental Studies, Sam Houston State University, Huntsville, Texas 77341, USA.
authors.forename: V
authors.initials: V
authors.lastname: Van Fleet-Stalder
authors.forename: T G
authors.initials: TG
authors.lastname: Chasteen
authors.forename: I J
authors.initials: IJ
authors.lastname: Pickering
authors.forename: G N
authors.initials: GN
authors.lastname: George
authors.forename: R C
authors.initials: RC
authors.lastname: Prince
mesh_terms: D002849:Chromatography, Gas / Q000379:methods; D003470:Culture Media / Q000737:chemistry; D012242:Rhodobacter sphaeroides / Q000254:growth & development / Q000378:metabolism*; D064586:Selenic Acid; D018036:Selenium Compounds / Q000378:metabolism*; D018038:Sodium Selenite / Q000378:metabolism*; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D003470:Culture Media; D018036:Selenium Compounds; D018038:Sodium Selenite; D064586:Selenic Acid