Researchers are training ‘mighty’ marine fungi to quickly eat polyurethane, one of our most common plastics.
In a world that relies on plastic, the time it takes to break down is a major problem. But scientists at the University of Hawaii have found a possible solution – marine fungi.
Plastic is the biggest ocean pollutant and plastic surfaces are the fastest growing habitat in this environment. Now researchers have discovered a species of fungi around the island of O’ahu that is eating polyurethane plastic.
They are investigating whether the fungi could be an innovative way to recycle and remove plastic from nature. Initial research looks promising.
But plastic experts claim that biodegradable plastic solutions are just one approach to combat the plastic pollution crisis. The other? To reduce plastic production in the first place.
Several microbes are already being tested to tackle plastic pollution
While our global reliance on plastics has grown due to their cheap, strong and useful nature, plastic never actually decomposes. Instead, when exposed to sunlight, heat and physical force, it breaks down into microplastics.
Researchers at the University of Hawaii (UH) in Mānoa believe that marine fungi is a “promising and largely untapped” solution to the removal of plastic waste from both on land and in our waters.
Eight million pieces of plastic pollution make their way into the ocean every day, according to a 2009 study. This has led to harrowing buildups in our seas, such as the Great Pacific Garbage Patch, a massive collection of marine debris in the Pacific Ocean and not far from Hawaii that’s three times the size of France.
Many of these plastics contain concentrations of harmful chemicals, such as phthalates and bisphenol A, which can damage our marine ecosystems. Human health is also at risk – one in three fish caught for human consumption now contains plastic.
“Plastic in the environment today is extremely long-lived, and is nearly impossible to degrade using existing technologies,” said Ronja Steinbach, who led this research as a marine biology undergraduate student at the UH Mānoa College of Natural Sciences.
Several microbes, including bacteria and land-growing fungi, are already being tested for their ability to break down plastics. If any prove successful, it’s expected that biotechnology will allow these solutions to be used on an ‘ecologically relevant scale’.
However, this is the first time that science has looked at marine fungi. Researchers made the breakthrough after taking a large sample of fungi that they isolated from sand, seaweed, corals, and sponges in Hawaii’s nearshore to study.
Currently, less than 1 per cent of marine fungi are known to science, as “very few people study fungi in the ocean,” said Steinbach.
The marine fungi could be conditioned to degrade plastic faster
“Fungi possess a superpower for eating things that other organisms can’t digest (like wood, or chitin), so we tested the fungi in our collection for their ability to digest plastic,” said Anthony Amend, Pacific Biosciences Research Center professor.
The team filled small petri dishes with polyurethane, a common plastic most frequently used in medical and industrial products, and measured whether and how fast the fungi could consume it. Then, the researchers took the fastest-growing fungi and experimented with it to see if, over time and with the greatest exposure to the polyurethane, the fungi could eat plastic faster and more efficiently. The results were positive.
“We were shocked to find that more than 60 per cent of the fungi we collected from the ocean had some ability to eat plastic and transform it into fungi,” said Steinbach.
“We were also impressed to see how quickly fungi were able to adapt. It was very exciting to see that in just three months, a relatively short amount of time, some of the fungi were able to increase their feeding rates by as much as 15 per cent.”
Now the UH Mānoa are trying to better understand the fungi at a cellular and molecular level to see how they degrade these compounds.
The researchers are also looking at other marine fungi to see if they, too, can eat different types of plastics that are harder to degrade and are larger sources of marine pollution.
They hope any solutions that they find could be part of an extensive future cleanup of beaches and seas.
Experts warn that legislation is critical to reduce plastic production first
Without commenting on the specific science, Dr Antaya March, director of the Global Plastics Policy Centre at the University of Portsmouth believes that this development is “innovative and promising”.
She says that “measures that help to manage waste and pollution are indeed valuable as part of the suite of approaches needed.” Yet she also thinks that reducing plastic production is just as integral and calls for a more “balanced approach” to plastic policy.
“It is also important to contextualise technological solutions such as these within the broader framework of global plastic management policies.
“The focus on end-of-life solutions such as biodegradation should not overshadow the imperative need for upstream strategies, primarily national and global legislation aimed at reducing plastic production.”
March believes that we should be “changing our relationship with single-use items, and reducing the volume of plastics produced and subsequently entering our ecosystems”. This is currently the subject of fierce debate in the negotiations for a Global Plastics Treaty.
Likewise, conservation NGOs suggest that research in this area is still limited and that there are “other proven solutions that already exist that can effectively address plastic pollution.”
“Preventing plastic from entering marine environments in the first place is far more effective than attempting to clean it up after the damage is done,” says Falco Martin, programme officer for Marine Plastics at the conservation charity Fauna & Flora.
“While it is interesting to see potential natural innovative solutions to the plastic pollution crisis, like marine fungi degrading plastics, they should not be seen as a silver bullet,” says Martin.
“Global legislation that restricts single-use plastics, detoxifies plastics and promotes more sustainable product design in packaging for example, would have a far greater effect.”
