Technology.am (Oct. 8, 2009) — Researchers reported the presence of bacteria on gold surfaces but have never clearly elucidated their role. Now, Australian scientists has found
that the bacterium Cupriavidus metallidurans catalyses the biomineralisation of gold by transforming toxic gold compounds to their metallic form using active cellular mechanism.
Since scientist discovered a number of years ago that the metal-resistant bacterium Cupriavidus metallidurans occurred on gold grains from two sites in Australia. They found the same organism on grains from both sites that are 3500 km apart, in southern New South Wales and northern Queensland.
The study points to their involvement in the active detoxification of gold complexes leading to formation of gold biominerals”, explains Frank Reith, leader of the research and working at the University of Adelaide.
The experiments showed that C. metallidurans rapidly accumulates toxic gold complexes from a solution prepared in the lab. This process promotes gold toxicity, which pushes the bacterium to induce oxidative stress and metal resistance clusters as well as an as yet uncharacterized gold-specific gene cluster in order to defend its cellular integrity.
This leads to active biochemically-mediated reduction of gold complexes to nano-particulate, metallic gold, which may contribute to the growth of gold nuggets.