Fate of selenate and selenite metabolized by Rhodobacter sphaeroides

• Published in: Applied and environmental microbiology Vol. 66; no. 11; pp. 4849 - 4853
• Main Authors: VAN FLEET-STALDER, Verena, CHASTEEN, Thomas G, PICKERING, Ingrid J, GEORGE, Graham N, PRINCE, Roger C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.11.2000
• Subjects: Bacteria; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Chemical elements; Chemistry; Chromatography, Gas - methods; Culture Media - chemistry; Environmental Microbiology and Biodegradation; Freshwater; Fundamental and applied biological sciences. Psychology; Microbiology; Mission oriented research; Physiology and metabolism; Rhodobacter sphaeroides; Rhodobacter sphaeroides - growth & development; Rhodobacter sphaeroides - metabolism; Selenic Acid; Selenite; Selenium Compounds - metabolism; Sodium Selenite - metabolism; Spectrum Analysis - methods; Rhodospirillales; Rhodobacter sphaeroides; Microorganism culture; Bacteria; Selenates; Rhodospirillaceae; Selenium; Metabolism; Selenites; Rhodospirillineae
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.66.11.4849-4853.2000

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.