Kamal Ghorui
In Western Australia’s goldfields, researchers have discovered a strain of the fungus known as Fusarium oxysporum that has an actual ‘Midas touch.’ This organism has a pink colour and is capable of interacting with the mineral deposits below the ground, breaking them down into a liquid state, and ultimately growing solid gold crystals on the thread-like hyphae.The presence of gold on the hyphae of this fungus allows for increased growth rates and sizes compared to their non-gold-infected cell cultures. The researchers now plan to investigate further into using this biological alchemy to mine for precious metals on the Moon and Mars. By utilising fungal bio-mining technology, future missions will be able to utilise a terrestrial biological wonder to provide the foundation for extraterrestrial resource recovery infrastructure.
A fungus in Western Australia that eats gold
Researchers from CSIRO (Commonwealth Scientific and Industrial Research Organisation) discovered that Fusarium oxysporum is known to absorb gold from its surroundings through the process of dissolution and by precipitating this gold as nanoparticles onto the hypha (branching filaments). The process is highly reactive in nature and involves the production of superoxide by the fungi used to oxidise the gold, thus allowing for a coating of gold on the fungi.
Why the fungus prefers gold
Analysis published in the journal Nature Communications reveals that fungi that are coated with gold exhibit greater growth rates than those that are not coated with gold, compared to fungi that do not interact with gold. This suggests that the presence of gold could assist as a catalyst for biochemical reactions or assist in the uptake of other nutrients, thus giving a competitive advantage to the fungi in the extreme mineral-rich environments of the Australian outback.
How microbes replace heavy machinery
The exploration of microbes processing minerals, commonly known as bio-mining, is a hot topic in the studies of agencies such as NASA and the ESA concerning potential implementation in space. Due to the prohibitive cost of moving large amounts of heavy equipment to the Moon or Mars, invisible to the naked eye, workers like Fusarium oxysporum could potentially be employed to extract gold and other metals from regolith, or soil on other planets. The biological aspect of in-situ resource utilisation (ISRU) will support human presence in space over the long term in a more sustainable manner.
How biological signatures may eliminate the need for costly exploratory drilling
In addition to space use, this finding has many immediate applications on Earth as well. CSIRO scientists state that the presence of the gold-coated fungus found growing on the surface is an indicator to mining companies that deeper underground deposits of gold may exist in larger concentrations, and therefore may eliminate the need for expensive drilling for exploratory purposes by using biological indicators first.
