Dark-colored fungi devour radiation and convert it to fuel, researchers said on Tuesday in a study that may offer applications from more efficient solar cells to feeding astronauts in space.
The study may also explain why it feels so good to soak up the sun on the beach, the researchers report in the Public Library of Science journal PLoS ONE.
The fungi use the same compound as people do — melanin, the pigment that makes both skin and truffles dark.
“Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum — ionizing radiation — to benefit the fungi containing it,” Ekaterina Dadachova of the Albert Einstein College of Medicine in New York said.
“It’s pure speculation but not outside the realm of possibility that melanin could be providing energy to skin cells,” said Arturo Casadevall, chair of microbiology and immunology at Einstein.
Their experiment was fairly simple.
Casadevall was reading about fungi found growing in and around the reactor at Chernobyl, closed and heavily contaminated by an accident in 1986.
“It gave us the idea that maybe fungi use melanin to harness radiation,” Casadevall said in a telephone interview.
So they grew some fungi, some types with melanin and others without melanin, and zapped them with gamma radiation.
The dark fungi grew better when radiated.
Future astronaut food?
“It raises the possibility that there are pigments out there that allow us to capture a lot of energy,” Casadevall said.
Scientists have discovered life in recent years that does not rely on the sun — sulfur-eating bacteria and extremophiles that live deep beneath the sea or under Antarctic ice. Perhaps fungi can live in seemingly inhospitable places as well, said Casadevall, so long as there is some radiation.
“It shows you how nature is resilient and resourceful. Nature can use an energy source wherever it can find it,” Casadevall said.
Perhaps radiation-loving fungi could serve as a source of food for astronauts living in space for long periods, the researchers speculated.
“Fungi do very well in dark damp places and you could imagine that space is totally radioactive,” Casadevall said.
Casadevall said scientists should be able to adapt such pigments for various uses.
His lab will test fungi against a range of electromagnetic radiation, from ultraviolet light to visible light. They will also test species of edible fungi, including mushrooms.
