gold-forming bacteria

Scientists have just discovered that bacteria may be responsible for the growth of pure gold nuggets.
Bacteria structures have been tenuously identified before in gold grains. Now Frank Reith and colleagues have shown that gold flakes from mines thousands of kilometers apart both contain bacteria structures and biofilms - and have identified markers of over 30 species of microbes in gold grains.
One identified species - the appropriately named Ralstonia metallidurans, has been shown to survive in gold choloride solutions, apparently precipitating gold out of solution in an attempt to detox its environment.
The results were reported in Science, and coverage of the story can be found here.