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.
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, lies in a molecule excreted by the microbe that both shields the organism and transforms the poisonous ions into particles.
“This finding is the first demonstration that a secreted metabolite can protect against toxic gold and cause gold biomineralisation,” the process by which living organisms produce minerals, they wrote .
The molecule, delftibactin A, is capable of achieving this feat within seconds in pH-neutral conditions at room temperature.
Study co-author Nathan Magarvey said that though the study was not designed to show whether it would be viable to use germs to grow gold from water in the lab, such processes seem “distinctly possible.” .
Magarvey said the study may implicate D. acidovorans in secondary deposits such as nuggets found in rivers.
The bacterium, he added, is not found only on gold but also in the soil and in water. Still unclear, though, is what the organism feeds on.