Eureka! Bugs Build Nanoscale Gold Nuggets

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Wearing a halo of golden nanoparticles is a survival technique for one species of bacterium. And the same method that allows the bacterium to precipitate gold out of a solution may help extract gold from mine waste in the future.

For about a decade now, biochemists have known that Cupriavidus metallidurans find gold metal toxic, but can isolate the metal inside their cells. Biochemist Nathan Magarvey of McMaster University in Hamilton, Canada, and his team grew a colony of Delftia acidovarans, which is sometimes found in biofilms of C. metallidurans. When the team discovered the angelic nature of D. acidovarans, they conducted tests to determine how the bacterium produced the molecular-sized gold nuggets outside its cell wall.

Through the use of genetically engineered and unengineered bacteria, the Canadian team isolated a set of genes that work in combination with a chemical metabolite they dubbed delftibactin. Their study was published this weekend in the journal Nature Chemical Biology. And while Magarvey has secured the intellectual property rights for delftibactin, panning for gold in a Petri dish, isn’t yielding a microbial gold rush, yet.

“I wish I could say we’re up here in Canada growing kilos of gold everyday,” he told Nature News.

IMAGE: A gold nugget from a mine in Brazil. (Bertrand Rieger/Corbis)