Move over, Midas. A genetically modified version of a bacterium that extracts gold from its environment can signal the presence of the precious metal. The result could be a boon for prospectors.
Some bacteria are known to be associated with gold deposits, but it has been unclear whether they play a role in its production聽鈥� and if so, what that is.
Now of the University of Adelaide, South Australia, has found that dissolved gold is harmful to the bacterium Cupriavidus metallidurans, as it forms a toxic sulphur-containing compound when it is absorbed from the environment. This compound inhibits the bacterium鈥檚 enzyme function, prompting the distressed microbe to activate a cluster of 鈥済old detox鈥� genes that produce enzymes able to convert the soluble gold compounds into harmless particles of metallic gold.
Advertisement
Hand-held prospector
Knowing how microbes do this will open up a whole new way of prospecting, says co-author of the University of Nebraska. Reith and Grass have developed a genetically modified version of C. metallidurans that produces a visible response when the detox genes are switched on.
鈥淲hen the microbes come into contact with gold, they flash a light that can be detected using a hand-held photometer,鈥� says Grass. He envisages that prospectors will be able to detect whether gold is present simply by taking a sample of soil and adding modified bacteria to it.
鈥淭here have been reports that bacteria can enhance the production of gold for some time,鈥� says , an environmental microbiologist at the Bayer School of Natural and Environmental Sciences at Duquesne University in Pittsburgh, Pennsylvania. 鈥淏ut this is the first time scientists have actually identified how they do it.鈥�
Journal reference: .
