Among the more peculiar organisms that inhabit our Earth exists a bacterium that turns water-soluble gold into microscopic nuggets of solid gold, scientists said Sunday. Chemists have often pondered why the germ Delftia acidovorans is frequently found on the surface of tiny gold nuggets. Its presence led scientists to speculate it may be creating the particles from soluble gold — ions of gold that are dissolved in water. But the puzzle was how D. acidovorans did this trick, as soluble gold is toxic. The answer, suggest researchers in Canada, lies in a molecule excreted by the microbe that both shields the organism ... (full story)