If you know a thing or two about fungus, you might be aware that it can thrive in the unlikeliest of conditions. From cardboard and jet fuel to asbestos and plastic, fungus “eats” just about anything. However, the real shocker came when scientists discovered a radiation-eating fungus growing inside the Chernobyl nuclear reactor, and we are not talking about radioactive compounds, which are known to facilitate fungal growth. This particular fungi, also known as “radiotrophic fungi,” eats radiation itself, and experts believe it can be used to create “sunblocks.”
The radiotrophic fungus was first discovered in 1991 around and inside the Chernobyl Nuclear Power Plant. It contains high amounts of melanin which helps it convert radiation into energy for growth.
In 1991, five years after the Chernobyl disaster, scientists found a strange black fungus, similar to mold on dirty shower curtains, growing on the walls of the nuclear reactor. It baffled them and made them question how something can grow in such an extreme environment that is filled with radiation. They soon realized that the fungus was not only immune to the lethal radiation, but it was actually attracted to it!
A decade or so later, researchers found that the fungus is rich in melanin, a pigment also found in human skin, and that it can perform radiosynthesis. In theory, radiosynthesis is a process, in which a living organism can capture and metabolize ionizing radiation, which essentially means turning gamma radiation into some kind of chemical energy that helps the organism grow. Scientists propose that radiosynthesis works in the same way photosynthesis does, but they are yet to ascertain whether the melanin-rich fungi use a multi-step pathway as chlorophyllous organisms do for photosynthesis.
After running tests on three species of fungus, researchers found that they all thrived in radiation.
Dr. Arturo Casadevall and Dr. Ekaterina Dadachova of New York’s Albert Einstein College of Medicine performed tests to see how three species of fungus, namely Wangiella dermatitidis, Cryptococcus neoformans, and Cladosporium sphaerospermum, react to gamma radiation from tungsten-188 and rhenium-188. The results, which were published in PLoS One, showed that all three types of fungi grow faster and thrive in the presence of radiation.
Previous studies had revealed that fungi that grow in contaminated regions try to reach different sources of radiation. Some fungi found in Chernobyl can even decompose radioactive materials such as hot graphite. Most of these fungi produce melanin, and experts believe that the pigment actually protects the fungi from various environmental stresses. Dadachova and her team also discovered that when exposed to radiation, the melanin molecules in the fungi changed shape, which made it four times more capable of performing metabolic chemical reactions.
According to Dadachova, such radiation-eating fungi may have existed in the early Cretaceous period, during which Earth experienced the “magnetic zero,” an event that stripped the planet of its protective shield against cosmic rays. Many species of plants and animals died out during this time, but deposits show large amounts of melanin-rich fungal spores.
Scientists are currently trying to harness the power and unique capabilities of the radiotrophic fungi.
After the discovery of the radiotrophic fungi, scientists started wondering whether melanin-rich human cells can also turn radiation into energy. According to Casadevall, there is no evidence, and it might be possible in theory, but the cells won’t produce enough energy to sustain a busy astronaut. On the other hand, researchers at NASA theorize that it might be possible to extract the radiation-absorbing power of the fungi to create a type of drug which would protect humans from toxic rays. Nuclear power plant engineers, cancer patients who are undergoing radiation therapy, and airline pilots could all benefit from such a drug.