A fungus at the site of the Chernobyl nuclear disaster has adapted to ‘feed’ on levels of radiation that would be lethal to most life forms.
Cladosporium sphaerospermum is a highly resilient black fungus that scientists have observed growing on the walls of the Number 4 reactor, which triggered the explosion and fire that destroyed the Chernobyl Nuclear Power Plant in 1986.
Scientists studying the fungus found it has adapted to use radiation as a source of energy, not unlike how plants derive energy from the sun.
The Chernobyl disaster was a nuclear meltdown that began on April 26 and led to the largest release of radioactive material into the environment in human history.
Following the tragic event, humans were evacuated from Chernobyl and the surrounding areas to avoid the extreme levels of radiation.
From then on, the site was known as the Chernobyl Exclusion Zone (CEZ).
The ability of C. sphaerospermum to survive in the CEZ is a testament to how life can emerge even in the harshest, most extreme environments, according to the researchers.
Studying this fugus has revealed ways it could be harnessed to protect humans from radiation, particularly during deep space missions.
Cladosporium sphaerospermum, a fungus living at the site of the Chernobyl nuclear disaster, has adapted to ‘feed’ on levels of radiation that would be lethal to most life forms
C. sphaerospermum gets its radiation-eating superpower from melanin, the pigment that gives humans their skin color.
Previous research published in the journal PLOS One confirmed that C. sphaerospermum can perform radiosynthesis by showing that it grows faster in high-radiation environments.
This laid the groundwork for later research published in the journal Current Opinion in Microbiology, which found that in this fungi, melanin absorbs gamma radiation and converts it to chemical energy through a process known as radiosynthesis.
Because of this, it is considered a radiotrophic fungi — ‘radio’ refers to radiation and ‘trophic’ refers to feeding or converting something into usable energy.
In human skin — and that of many other organisms — melanin acts as a shield against harmful UV radiation from the sun.
But in this fungi, ‘It does more than shield: it facilitates energy production,’ Rutgers University evolutionary biologist Scott Travers wrote in an article for Forbes.
Now, scientists believe they may be able to harness this superpower in order to create highly effective radiation shields that can protect astronauts during deep space missions.
The harsh radioactive environment of space is one of the biggest hurdles to long-duration human space missions.
The Chernobyl disaster was a nuclear meltdown that began on April 26 and led to the largest release of radioactive material into the environment in human history
Following the tragic event, humans were evacuated from Chernobyl and the surrounding areas to avoid the extreme levels of radiation. But some organisms have survived
In just one week on the ISS, astronauts are exposed to the equivalent of one year’s exposure on Earth, according to the European Space Agency (ESA).
On Mars, the radiation environment is even more intense. An astronaut on a mission to Mars could receive radiation doses up to 700 times higher than on our planet, the ESA has stated.
In a study that has not yet been reviewed by other scientists, researchers aboard the International Space Station (ISS) studied C. sphaerospermum’s ability to attenuate harmful radiation in a radioactive environment similar to the surface of Mars.
The research took place over a period of 26 days, and found that the fungus blocked and absorbed 84 percent of the space radiation and showed significant growth, indicating that its radiotrophic abilities are extendable to space environments.
The study is currently available on the pre-print server bioRxiv.
But C. sphaerospermum could have some useful applications on Earth, too.
Studies suggest this fungi is a powerful bioremediator, meaning it can be used to remove radioactive pollution from the environment.
Cleaning up radioactive sites like the CEZ is both challenging and dangerous, but radiotrophic fungi may provide a safer alternative to human-led cleanup efforts.
While scientists are still researching and developing ways to deploy radiotrophic fungi for this purpose, studies have yielded promising results.
Researchers at the University of Saskatchewan demonstrated that it is possible to ‘train’ microscopic black fungi to find and attenuate radiation sources. Their study was published in the journal Fungal Biology in 2020.
But C. sphaerospermum isn’t just known for its ability to feed on radiation. It is also uniquely resilient to low temperatures, high salt concentrations and extreme acidity, Travers explained.
‘Its ability to adapt to hostile environments has given researchers hope that it may hold clues for further studies into stress tolerance mechanisms, which could lead to advancements in biotechnology and agriculture,’ he wrote.
For example, genes responsible for this hardiness could be used to develop radiation-resistant materials or breed highly resilient crops, he explained.
