The Midas Bug – the bacterial alchemy of gold

The paper highlights the findings of a Cooperative Research Centre for Landscape Environments and Mineral Exploration (CRC LEME) project by CSIRO researcher, Dr Frank Reith.

Dr Reith’s research has shown that bacteria play a significant role in the formation of secondary gold grains.

His study of gold grains from the Tomakin Park and Hit or Miss gold mines in southern New South Wales and northern Queensland, respectively, led to a series of discoveries, which showed that specific bacteria present on these gold grains precipitate gold from solution.

“The origin of secondary gold grains is a controversial topic that is widely debated within the scientific community,” Dr Reith said.

“There are those who believe the grains are purely detrital, while others believe they form by chemical accretion.

“A third theory suggest that microbial processes are involved in gold grain formation which may be responsible for one of the largest gold deposits in the world, the Witwatersrand deposit in South Africa.”

Applying molecular biology techniques, Dr Reith discovered a living biofilm on the surface of gold grains collected. DNA profiling of this biofilm identified 30 bacterial species with populations unique to the gold grains when compared to the surrounding soils.

One species was identified on all of the DNA-positive gold grains from both locations. DNA sequence analysis of this species identified it as the bacterium Ralstonia metallidurans.

“The next step was to see if we could observe gold precipitation in the presence of a culture of this bacteria,” Dr Reith said.

“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.”

This research has significance for the mineral exploration industry – as current models of gold formation do not include a biological mechanism.

“There may be new opportunities for the bio-processing of gold ores now that we have discovered bacteria that precipitants gold out of solution,” Dr Reith said.

Media Contact

Klaus Regenauer-Lieb EurekAlert!

More Information:

http://www.csiro.au

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors