Uranium Bioaccumulation by a Citrobacter sp. as a Result of Enzymically Mediated Growth of Polycrystalline HUO_2PO_4

A Citrobacter sp. accumulates heavy deposits of metal phosphate, derived from an enzymically liberated phosphate ligand. The cells are not subject to saturation constraints and can accumulate several times their own weight of precipitated metal. This high capacity is attributable to biomineralization; uranyl phosphate accumulates as polycrystalline HUO_2PO_4 at the cell surface. The precipitated metal is indistinguishable from crystalline HUO_2PO_4\cdot4H_2O grown by chemical methods.