In short: Some fungi produce enzymes that break down plastic. Pestalotiopsis microspora, discovered in Ecuador's rainforest in 2011, can digest polyurethane even without oxygen — a discovery that scientists are now studying to help shrink landfill plastic waste.
What is a plastic-eating fungus?
Most fungi eat things like wood, leaves, and dead matter — but some fungi eat plastic. These fungi produce powerful chemicals called enzymes that can break apart plastic polymers, the long chains of molecules that make plastic so strong and hard to break down. The fungus then uses the broken-down plastic as food.
The rainforest discovery
In 2011, Yale University researchers made an extraordinary discovery in Ecuador's Amazon rainforest. They found a fungus called Pestalotiopsis microspora growing on plants — and it had an unusual talent: it could digest polyurethane, a tough plastic used in foam cushions, insulation, and many other everyday products.
The most remarkable discovery? The fungus could do this even without oxygen. Deep inside landfills, where oxygen is scarce, this fungus could still break down the plastic. The researchers published their findings in Applied and Environmental Microbiology, making it clear that this was something new and important.
How does Pestalotiopsis eat plastic?
Pestalotiopsis microspora produces an enzyme called a serine hydrolase. This enzyme works like tiny scissors, cleaving the ester bonds that hold the plastic together. Once those bonds are cut, the polymer chains fall apart into smaller pieces that the fungus can consume as food.
What makes this fungus special? Most microbes (bacteria and fungi) slow down or stop working when oxygen runs out. Pestalotiopsis microspora works just as well in both conditions — with oxygen and without it. This makes it uniquely suited to landfill conditions, where plastic sits in dark, airless piles for decades.
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What scientists are studying now
The discovery of Pestalotiopsis microspora sparked a wave of research. Scientists around the world are now looking for other plastic-eating fungi and studying their enzymes in detail.
Researchers have found that fungi produce many different types of enzymes for breaking down plastics:
- Hydrolases (including lipases and cutinases) cleave the bonds holding polymer chains together
- Oxidoreductases (like laccases and peroxidases) use oxygen to oxidize and break down plastics into smaller molecules
Different fungi excel at different plastics. Some are good at polyethylene terephthalate (PET) — the plastic in soft drink bottles. Others, like Aspergillus tubingensis (discovered at a landfill in Pakistan), can break down polyester. Scientists are still in the early stages, but the hope is that engineered versions of these enzymes could one day help shrink the mountains of plastic accumulating in landfills and oceans.
The short version
Fungi produce enzymes that can break down plastic. Pestalotiopsis microspora, found in the rainforest and studied since 2011, is remarkable because it digests polyurethane even in oxygen-free landfill conditions. Scientists are now studying many plastic-degrading fungi and their enzymes as a potential tool to tackle plastic waste.
Curious questions
Can Pestalotiopsis microspora really eat plastic?
Yes. Yale researchers discovered in 2011 that this fungus produces enzymes that break down polyurethane. It cleaves the bonds holding the plastic polymer together, allowing it to use the plastic as food.
Why does it work in landfills without oxygen?
Most microbes slow down or stop working without oxygen, but Pestalotiopsis microspora works just as well in oxygen-free environments. This makes it unique and valuable for landfill conditions, where plastic piles up in dark, airless spaces.
Will this fungi solve the plastic problem?
Not yet. Scientists are still in the early stages of research, studying these fungi and their enzymes in laboratories. It could take years to engineer enzymes that work fast and efficiently enough for real-world use at scale.
Are there other plastic-eating fungi?
Yes. Scientists have found several fungi that degrade plastics, including Aspergillus tubingensis (which breaks down polyester) and others. Different fungi produce different enzymes, each suited to breaking down different types of plastic.
Sources & further reading
- Applied and Environmental Microbiology — Biodegradation of Polyester Polyurethane by Endophytic Fungi (2011)
- PMC/NIH — Fungal Enzymes Involved in Plastics Biodegradation
- Bioresources and Bioprocessing — Biodegradation of Plastic Polymers by Fungi (2022)
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