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Fate of Selenate and Selenite Metabolized by Rhodobacter sphaeroides

2000; American Society for Microbiology; Volume: 66; Issue: 11 Linguagem: Inglês

10.1128/aem.66.11.4849-4853.2000

1098-5336

Verena Van Fleet‐Stalder, Thomas G. Chasteen, Ingrid J. Pickering, Graham N. George, Roger C. Prince,

Kidney Stones and Urolithiasis Treatments

ABSTRACT Cultures of a purple nonsulfur bacterium, Rhodobacter sphaeroides , amended with ∼1 or ∼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.