Using DNA profiling on gold grains collected from two gold mines in Australia, scientists have been able to single out a bacteria, Ralstonia metallidurans, that is capable of precipitating dissolved gold.

"By placing a culture of the R. metallidurans in the presence of dissolved gold, which is highly toxic to microorgansims, I observed active gold precipitation.

"A unique attribute of R. metallidurans is that it is able to survive in concentrations of gold that would kill most other micro-organisms."

As the scientists say, this present great potential in gold mining using bio-precipitation as a method to retirieve gold from solution. Their discoveries were published last month in Science.

[Photo: Bacterioform-gold1: Coloured scanning electron image of bacterioform gold on a gold grain from the Hit or Miss Mine in northern Queensland. courtesy of CSIRO]