Can Fungi Break Down Plastic? What Research Shows

Every few months a headline announces a “plastic-eating fungus”. The idea is irresistible: a living organism that could quietly digest the plastic piling up in landfills and oceans. Some of these discoveries are real, and a few are genuinely impressive. But between a petri dish and a polluted beach there’s a long way to go.

This article looks at the best-known plastic-degrading fungi, what the studies actually measured, and why scientists say fungi won’t solve the plastic problem on their own.

Why scientists are looking at fungi

Fungi are expert decomposers. Wood-rotting species break down lignin and cellulose, some of the toughest materials in wood, using enzymes they release into their surroundings. Our article on mycoremediation explains how those same enzymes are being tested against oil, pesticides and other pollutants. Plastic is the next obvious target.

The scale of the problem explains the interest. A 2018 UN News report on Kew’s first State of the World’s Fungi report noted that at least eight million tonnes of plastic enter the sea each year. The Royal Netherlands Institute for Sea Research (NIOZ) says humans now produce over 400 billion kg of plastic a year, an amount expected to at least triple by 2060.

How many fungi can degrade plastic?

More than you might think. A 2022 review in the Journal of Fungi by Ekanayaka and colleagues counted “more than 200 records of fungi capable of degrading different plastic types”. It found these fungi spread across 11 classes in three major fungal groups, with Aspergillus and Penicillium moulds among the most commonly reported.

The review covered conventional plastics such as PET, polyethylene, polypropylene, PVC and polystyrene, as well as bio-based plastics such as PLA. Many of the fungi on the list are moulds rather than mushrooms, but the review’s three groups also include Basidiomycota, the group that contains most mushroom-forming fungi.

Five discoveries that made headlines

Year	Fungus	Plastic	Where it was found	Key result
2011	Pestalotiopsis microspora	Polyester polyurethane	Collected by Yale students on a rainforest course	Grew on the plastic as its only food, with or without oxygen
2017	Aspergillus tubingensis	Polyurethane	A waste disposal site in Islamabad, Pakistan	Broke down polyurethane in weeks rather than decades, according to Kew
2022	More than 200 records	Many types	Worldwide	Summarised in the Journal of Fungi review
2023	Aspergillus terreus and Engyodontium album	Polypropylene	Soil and plant fungi, tested in Sydney	25 to 27% degraded after 90 days, after pretreatment
2024	Parengyodontium album	Polyethylene	Floating plastic in the North Pacific	About 0.05% broken down per day, but only after UV exposure

The rainforest fungus that ate polyurethane

In 2011, a team led from Yale University published a study in Applied and Environmental Microbiology. Students on the university’s Rainforest Expedition and Laboratory course had collected endophytes, fungi that live inside plants without harming them. The team screened several dozen of these fungi for their ability to break down polyester polyurethane, a durable plastic used in foams and coatings.

Several fungi degraded it, but two isolates of Pestalotiopsis microspora stood out. They could grow on polyurethane as their “sole carbon source” both with and without oxygen. Growth without oxygen caught attention because, as Mongabay’s report explained, deep layers of landfill have little oxygen. The researchers linked the activity to an enzyme called a serine hydrolase. They described endophytes as “a promising source of biodiversity” for bioremediation, a careful phrase rather than a promise of landfill clean-up.

The landfill mould from Pakistan

Kew’s 2018 State of the World’s Fungi report highlighted Aspergillus tubingensis. According to UNEP’s summary, a team of scientists from China and Pakistan found it in 2017 at a waste disposal site in Islamabad, where it was breaking down polyurethane. The fungus can break the bonds between the plastic’s molecules in weeks.

Senior Kew scientist Ilia Leitch was cautious. She said speeding up the process depends on “understanding how the fungi break down these bonds and what the optimal conditions are”, which is still being worked out.

Fungi that tackle polypropylene

Polypropylene is notoriously hard to recycle. In 2023, researchers at the University of Sydney reported in npj Materials Degradation that two common fungi, Aspergillus terreus and Engyodontium album, could break it down. The university’s news release says polypropylene makes up about 28% of the world’s plastic waste, but only about 1% of it is recycled.

The results came with important conditions:

The plastic was first treated with UV light, heat or a chemical called Fenton’s reagent.
After UV or heat treatment, the fungi degraded 21% of the plastic in 30 days and 25 to 27% in 90 days.
The work was done in petri dishes in the laboratory.
The study didn’t establish how the fungi broke the plastic down, or whether they used it as food.

Professor Ali Abbas, who supervised the work, noted that “our study did not yet carry out any optimisation of the experimental conditions”, so the team hopes to make the process faster.

The ocean fungus

In June 2024, NIOZ reported that a marine fungus, Parengyodontium album, could break down polyethylene, which NIOZ describes as the most abundant plastic that has ended up in the ocean. The team, which included researchers from Utrecht University and The Ocean Cleanup, found the fungus on plastic litter collected from the North Pacific. Their results were published in Science of the Total Environment.

Using plastic labelled with a traceable form of carbon, the researchers showed that most of the carbon the fungus used from the plastic ended up as carbon dioxide. The catch is that the fungus only broke down polyethylene that had first been exposed to UV light. In NIOZ’s words, plastic that sinks before reaching sunlight is unlikely to be degraded by this fungus. The breakdown rate was about 0.05% per day in the lab, which works out at roughly 1.5% a month by simple arithmetic.

NIOZ adds that only four plastic-degrading marine fungi were known before this discovery, and researcher Annika Vaksmaa expects more to be found in deeper parts of the ocean.

Why fungi won’t fix plastic pollution yet

The discoveries are real, but the review and the researchers themselves point to the same limits.

Limitation	What the evidence says
Mostly lab studies	The Sydney study used petri dishes, and the NIOZ rates were measured in the lab
Pretreatment needed	Polypropylene and polyethylene were only broken down after exposure to UV light or heat
Slow rates	The marine fungus broke down about 0.05% of the plastic a day
Uncertain measurements	Ekanayaka’s review warns that “many studies have failed to differentiate losses caused by the leaching or degradation of polymers”
Unknown mechanisms	The Sydney team didn’t yet know how the fungi broke down the plastic
Gaps in research	The review found only about 25% of records come from marine environments, despite the scale of ocean pollution

The point about measurement matters. Plastic can lose weight because additives leach out, not only because the polymer itself is being broken down. The 2022 review calls for studies in real environments that measure weight loss, changes in the plastic’s structure and the genes or enzymes responsible.

The carbon question also matters. When fungi digest plastic, much of it becomes carbon dioxide, as the NIOZ team showed. NIOZ says the amount released is small and comparable to what people breathe out, so it’s not expected to create a new problem. Even so, it’s a reminder that biodegradation turns plastic into other things rather than making it vanish.

What could fungi realistically do?

Researchers see fungi as one tool among many. Possible future uses include:

Treating plastic waste in controlled facilities, where pretreatment and conditions can be managed. The Sydney team hopes to build a small pilot.
Finding better enzymes. Identifying the enzymes fungi use could help scientists design faster, more targeted processes.
Discovering new species. Kew’s report noted that only about 144,000 of an estimated 3.8 million fungal species have been named, so many plastic-degrading fungi may still be unknown.

Fungi are also being used to replace plastic rather than digest it. Packaging and insulation grown from mycelium are already on sale, as our article on mycelium materials explains. If you’re new to the difference between a mushroom and its mycelium, our guide to fruiting bodies vs mycelium is a good starting point.

Can you try this at home?

Not really. These were controlled laboratory experiments, mostly with moulds such as Aspergillus, and there’s no tested home method for breaking down plastic with fungi. If you’d like to experiment with fungi and waste, growing oyster mushrooms on straw or coffee grounds is a safer, well-tested project.

The bottom line

Some fungi really can break down plastics, including polyurethane, polypropylene and polyethylene. But most results come from lab tests, often after the plastic has been pretreated, and the rates are slow. Scientists see fungi as a promising area for research, not a quick fix. The next time you see a headline about a plastic-eating fungus, it’s worth asking three questions: was it tested outside the lab, was the plastic pretreated, and how fast did it work? Reducing plastic use and improving recycling remain the most effective steps for now.

Sources and further reading

Featured image: microplastic fragments under a microscope, U.S. Geological Survey Environmental Health Program (USGS, public domain).

Can Fungi Break Down Plastic? What the Research Really Shows

Why scientists are looking at fungi

How many fungi can degrade plastic?

Five discoveries that made headlines