- For the first time microbes have been shown to tinker with gold deposits.
- Bacterial biofilms dissolve gold, which makes it available for re-depositing in purer form elsewhere.
- The bacteria have been identified and so someday hand-held biosensors may help in gold prospecting.
Gold nuggets are often the creations of bacterial biofilms, say Australian researchers who have demonstrated the process and 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.