Bacteria can make gold nuggets

Washington, Sep 2 (ANI): In a first of its kind study, Aussie researchers have found that bacterial biofilms can go on to create gold nuggets-a feta that could help prospectors use biosensors to zero-in on where clumps of the precious metal may lie.

Researchers have not only demonstrated the process, but have even identified the bacteria at work.

Layers of bacteria can actually dissolve gold into nanoparticles, which move through rocks and soils, and then deposit it in other places, sometimes creating purer "secondary" gold deposits in cracks and crevices of rocks.

The process overturns the long-held belief by some scientists that gold ore is created only by "primary" physical geological processes.

By looking at the DNA in biofilms that grow on gold grains collected from the Prophet gold mine in southeast Queensland, Australia , the University of Adelaide's Frank Reith and his colleagues discovered that 90 percent of the bacteria were of just two species Delftia acidovorans and Cupriavidus metallidurans.

The bacteria share genes that make them resistant to the toxic effects of heavy metals.

"It's the first time we actually see the mechanism laying on top of the gold grain," Discovery News quoted Joel Brugger of the South Australian Museum and University of Adelaide, a co-author on the study as saying.

"We tagged the DNA and saw the beautiful active biofilm (dissolving the gold). That was very interesting because gold in soluble form is very toxic," said Brugger.

That dissolved gold can then be redeposited in other places in a much purer form.

The discovery is especially important because it could point to a new high tech way to prospect for gold.

The presence of the bacteria could be a quick way to test if gold is present in the ground, suggested Brugger.

Field geologists could even someday use biosensors that are tuned to detect the genes of these gold-specific microbes.

A report about the discovery appears in the September issue of the journal Geology. (ANI)