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Microbes derive energy from redox chemistry of phosphorus
Microbes that derive their energy by oxidizing phosphite ion (HPO32-) to phosphate (HPO42-) have been isolated from marine sediments in Venice [Nature,406, 37 (2000)]. German microbiologists Bernhard Schink of the University of Konstanz and Michael Friedrich of the Max Planck Institute for Terrestrial Microbiology, Marburg, who found the anaerobic bacterium, think it is the first example in microbial energy metabolism of a redox reaction involving phosphorus. As the bacteria oxidize phosphite, they simultaneously reduce sulfate ion to hydrogen sulfide. The strain also oxidizes fumarate and malate to carbon dioxide, which provides all its carbon needs. Although phosphite and other reduced phosphorus compounds are unstable on today's oxygen-rich Earth, they may have been much more abundant and important at the time in the planet's history when life was first evolving, the researchers note. Thus, they propose, the ability to derive energy from phosphite chemistry may represent an ancient evolutionary trait.
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