Reduction of uranium(VI) phosphate during growth of the thermophilic bacterium Thermoterrabacterium ferrireducens

The thermophilic, gram-positive bacterium Thermoterrabacterium ferrireducens coupled organotrophic growth to the reduction of sparingly soluble U(VI) phosphate. X-ray powder diffraction and X-ray absorption spectroscopy analysis identified the electron acceptor in a defined medium as U(VI) phosphate [uramphite; (NH4)(UO2)(PO4) - 3H(2)O] while the U (IV)-containing precipitate formed during bacterial growth was identified as ningyoite [CaU(PO4)(2) - H2O]. This is the first report of microbial reduction of a largely insoluble U(VI) compound.