Science

Gold-mining fungi could guide human prospectors

Gold-mining fungi could guide ...
Fashionable fungi: A colored image shows the particles of gold collected by the fungus species fusarium oxsporium
Fashionable fungi: A colored image shows the particles of gold collected by the fungus species fusarium oxsporium
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Fashionable fungi: A colored image shows the particles of gold collected by the fungus species fusarium oxsporium
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Fashionable fungi: A colored image shows the particles of gold collected by the fungus species fusarium oxsporium

Shiny, pretty and useful in electronics, gold has been prized by humans for millennia, but we're not the only ones out there prospecting. Scientists from Australia's CSIRO have now found a fungus species that mines for gold, and even decorates itself with the precious particles. Following the fungus could be a new, environmentally-friendly way to find large underground gold deposits.

Fusarium oxsporum is a pretty common soil fungus, and like most fungi, this species is known to play a role in helping certain metals move around the world. That usually only applies to chemically active metals, which should logically rule out gold – but flaunting logic, fusarium oxsporium has now been found to adorn itself in gold.

"Fungi can oxidize tiny particles of gold and precipitate it on their strands – this cycling process may contribute to how gold and other elements are distributed around the Earth's surface," says Tsing Bohu, lead author of the study. "Fungi are well-known for playing an essential role in the degradation and recycling of organic material, such as leaves and bark, as well as for the cycling of other metals, including aluminum, iron, manganese and calcium. But gold is so chemically inactive that this interaction is both unusual and surprising – it had to be seen to be believed."

The scientists aren't exactly sure why the fungus is bothering to mine gold, but there does appear to be some biological advantage to it. Gold-coated fungi were found to grow larger and spread faster than others, and that in turn seems to help the rest of the soil community become more biodiverse.

The discovery, made by scientists at Australia's national science agency (CSIRO), the University of Western Australia, Murdoch University and Curtin University, could have several benefits. The fungi could be a useful tool for recovering gold from waste products, such as electronics or even sewage. Or looking for blinged-out fungi on the surface could indicate the presence of larger deposits underground.

"The industry is actively using innovative exploration sampling techniques, such as gum leaves and termite mounds, which can store tiny traces of gold and can be linked to bigger deposits below the surface," says Ravi Anand, an author of the study. "We want to understand if the fungi we studied, known as fusarium oxsporum – and their functional genes – can be used in combination with these exploration tools to help industry to target prospective areas in a way that's less impactful and more cost-effective than drilling."

The next steps for the team are to investigate whether the golden fungi are a good indication of sub-surface gold deposits, and perhaps to figure out what the fungi are doing with the gold in the first place.

The research was published in the journal Nature Communications.

Source: CSIRO

3 comments
Andrew Keim
This is great and all, but the fungi also infects and kills Banana, and plantain orchards in droves.... let's hope this idea doesn't take off or we will have very few Banana farms remaining... Apparently it's one of the worst pathogens for many different plants. https://en.wikipedia.org/wiki/Fusarium_oxysporum_f.sp._cubense
ljaques
Why do the science feeds pick up these pre-hint, pre-whiff, pre-fact "studies" and publish them? Because they sound good? A real study would have suggested how much fungus it would take to could produce, say, a milligram of gold, how it was processed, what the ecological ramifications of harvest were, etc. As it is, the articles are all fluff. And here is another (somewhat less dramatic) picture of it: https://www.the-scientist.com/news-opinion/fungus-found-in-australian-soil-can-oxidize-gold-65933 P.S: The words "may", "might", and "could" are not sound scientific testing terms...well, except maybe in this anno Algore era we live.
Michael Irving
@ljaques: The story is simply about the discovery of a fungus that oxidizes gold, which is interesting in its own right. The intention isn't to harvest gold *from* the fungus – as you said, that's not economically sound at all. The mention of using it to retrieve gold from old electronics is, at this point, merely a suggested application down the track. The main scientific value is that mining companies could look for these fungi in the wild to find larger deposits underground, which would save them drilling to find new places to mine properly.