Fungi That Eat Plastic: How They Work and What It Means

Hundreds of fungal species can break down synthetic plastics, using enzymes originally evolved to digest tough natural polymers like lignin in wood. Researchers have now documented plastic-degrading ability across at least eleven fungal classes spanning three major branches of the fungal family tree, with more species identified every year.¹ The science is genuinely exciting, but it also sits at an awkward stage: lab results are promising, and real-world deployment is still a distant prospect.

How Many Fungi Can Actually Do This

The short answer is a lot more than anyone expected a decade ago. A 2022 review cataloging known plastic-degrading fungi found representatives in eleven classes spread across the phyla Ascomycota, Basidiomycota, and Mucoromycota. The largest concentration of plastic degraders falls within the Eurotiomycetes, a class that includes familiar mold genera like Aspergillus and Penicillium.¹ But the ability is not confined to any one ecological niche. Plastic-eating fungi have turned up in rainforest soils, compost heaps, marine debris, and even mangrove sediments.

Marine environments have been a particularly productive place to look. A 2024 study testing 68 fungal isolates collected from ocean settings found that 42 of them, roughly 62%, could detectably degrade polyurethane in lab conditions. The fastest performer, a species called Gibberella intricans, cleared an entire test plate in just 19 days.² Another marine find, the fungus Parengyodontium album, was isolated from floating plastic debris in the North Pacific and shown to mineralize polyethylene, converting it all the way to CO₂.³ The breadth of species involved suggests that plastic degradation is not some rare evolutionary trick but something many fungi stumble into because of the enzymes they already carry.

The Enzyme Toolkit Behind Plastic Digestion

Fungi did not evolve to eat plastic. Synthetic polymers have only existed for about a century, far too short for meaningful evolutionary adaptation. What fungi did evolve, over hundreds of millions of years, are powerful enzymes for breaking down lignin, the tough structural polymer in wood. It turns out that these lignin-digesting enzymes can also attack the chemical bonds in several types of plastic.

The main players are a group called ligninolytic enzymes, primarily laccases and peroxidases. Laccases use copper to catalyze oxidation reactions, while peroxidases use iron-containing heme groups to generate reactive oxygen species. Both can chip away at the long carbon chains in polyethylene and similar plastics.⁴ White-rot fungi, the group best known for decomposing dead wood in forests, are especially well equipped because they produce these enzymes in abundance.⁵

Not every plastic-degrading fungus relies on the same enzymatic approach. When researchers studied how Pestalotiopsis microspora breaks down polyurethane, they found the critical enzyme was not a laccase or peroxidase but a serine hydrolase, a roughly 21-kilodalton protein that attacks the ester bonds in polyurethane’s structure. The fungus only produced this enzyme when it was actually growing on polyurethane as a food source, suggesting the gene is switched on by the presence of the plastic itself.⁶ So while the headline is often “fungi eat plastic,” the biochemical reality is that different fungi use different enzymatic strategies depending on which type of plastic they encounter.

Some fungi also produce biosurfactants, notably proteins called hydrophobins, that help the enzymes gain access to plastic surfaces. Plastic is hydrophobic and resists wetting, which means enzymes dissolved in water have trouble making contact with the polymer chains. Hydrophobins act as a kind of molecular bridge, coating the plastic surface and making it accessible to the degrading enzymes.⁴

Which Plastics Are Vulnerable and Which Are Not

Fungi do not attack all plastics equally. Polyurethane (PU) and polyethylene terephthalate (PET) are among the more susceptible types, in part because their molecular structures contain ester bonds that enzymes can hydrolyze. Polyethylene (PE), especially the low-density variety used in bags and films, can also be degraded, though more slowly and often with the help of pretreatment. Studies have shown measurable erosion of linear low-density polyethylene sheets treated with fungi like Schizophyllum commune and Lentinus sajor-caju.⁷

Polypropylene stands out as a much harder target. PP is the second most commonly produced plastic in the world and is used in everything from food containers to car bumpers. Yet as of 2023, microbial degradation of additive-free polypropylene remained, as one research group put it, “elusive.”⁸ PP’s carbon backbone lacks the ester or urethane bonds that give enzymes a convenient chemical handle. Some fungi from the genera Coniochaeta and Pleurostoma have shown early signs of PP degradation, but the rates are extremely low compared to what has been achieved with PU or PE.

Plasticizer additives represent a separate angle entirely. Phthalates like diisobutyl phthalate are often blended into plastics to make them flexible, and fungi can attack these additives independently of the polymer backbone. In mangrove-sourced isolates, an Aspergillus strain degraded about 76% of diisobutyl phthalate in just 14 days.⁹ Degrading the additives is useful from an environmental perspective because phthalates are endocrine disruptors, but breaking down the additive does not break down the plastic itself. Reducing toxicity is one thing; reducing the mass of a garbage patch is quite another.

Why Sunlight Matters So Much

One of the most consistent findings across studies is that UV pretreatment dramatically improves fungal degradation of polyethylene. When researchers tested Parengyodontium album against PE, the biodegradation rate for UV-pretreated polyethylene was about 0.044% per day. Without UV pretreatment, incorporation of plastic-derived carbon into the fungal cells was undetectable.³ The researchers concluded that initial photodegradation of PE was “crucial” for the fungus to metabolize the carbon.

UV light works by cracking long polymer chains into shorter fragments and introducing oxygen-containing functional groups like carbonyls and hydroxyls onto the plastic surface. These chemical changes give fungal enzymes something to grab onto. In untreated polyethylene, the surface is an almost featureless expanse of carbon-carbon bonds with very little for an enzyme to attack. After UV exposure, it becomes chemically rougher and more reactive. Similar pretreatment effects have been observed in studies using mineral oil amendments and accelerated aging, all of which create the surface chemistry that fungal enzymes need to get started.¹⁰

This matters for real-world applications. Plastic buried in a landfill or sitting on the ocean floor receives minimal UV exposure, which means fungi encountering it in those environments may not be able to degrade it efficiently. Plastic floating at the ocean surface or scattered on land gets far more sunlight. The implication is that where plastic ends up physically affects whether biology can deal with it, and any engineered bioprocessing system would likely need to include an abiotic weathering step before the fungi do their part.

Training Fungi to Work Faster

One of the more intriguing recent findings is that fungi can be conditioned to degrade plastic more quickly through repeated exposure. In the marine fungal study mentioned earlier, researchers grew fungi on polyurethane over multiple cycles and then compared their performance to unconditioned counterparts. Three species showed clear improvements: Aureobasidium sp. cleared 19% more of the plate, Penicillium coccotrypicola cleared 20% more, and Penicillium steckii cleared 11% more after conditioning.²

This is not genetic engineering. It is closer to a training regimen: the fungi are simply exposed to plastic repeatedly, and natural regulation of gene expression shifts their metabolism to become better at using it. Whether this adaptation is stable over many generations or requires continuous selective pressure is still an open question, but it suggests that even without high-tech interventions, there are straightforward ways to improve performance.

Fungal-Bacterial Teams

Fungi rarely work alone in nature. Soils, compost piles, and ocean biofilms are complex communities where fungi and bacteria interact constantly. Several research groups have explored whether fungal-bacterial consortia outperform either organism working solo, and the answer is generally yes.

A study on polyethylene degradation found that combining the fungus Fusarium oxysporum with the bacterium Bacillus subtilis enhanced degradation efficiency compared to either organism alone.¹¹ Separately, experiments on low-density polyethylene mulch films tested an Aspergillus-only fungal consortium against a mixed fungal-bacterial co-culture involving Aspergillus fumigatus and Pseudomonas aeruginosa. The fungal-only consortium achieved better weight loss of the plastic, around 3.7%, but the mixed culture produced distinct chemical changes in the polymer surface, suggesting the two approaches attack the plastic in complementary ways.¹⁰

The logic is straightforward. Fungi are good at the initial physical colonization, since their hyphae can penetrate and physically disrupt a surface in ways that free-floating bacteria cannot. Bacteria, meanwhile, are often better at metabolizing the small molecular fragments that fungal enzymes release. A well-designed consortium could have fungi roughing up the surface and releasing breakdown products, while bacteria mop up those products and convert them further. This kind of division of labor mirrors what happens naturally in compost and soil.

The Gap Between Lab Results and Real-World Impact

This is where the honest reality check belongs. Lab-scale degradation rates, while impressive in context, are nowhere near the scale needed to address the global plastic waste problem. Consider the numbers: as of the mid-2010s, roughly 6.3 billion metric tons of plastic waste had been generated worldwide, and about 79% of that ended up in landfills or the environment.¹ Projections suggest that figure could reach 12 billion metric tons by 2050. Against that backdrop, a fungus degrading PE at 0.044% per day in a carefully controlled lab environment represents a biological proof of concept, not a solution you could deploy at a waste processing facility tomorrow.

Several practical challenges stand between the lab and any real application:

Speed: Even the fastest fungal degraders take weeks to clear small test plates. Scaling that to tons of mixed waste is a fundamentally different engineering problem.
Selectivity: Real-world plastic waste is a chaotic mix of polymer types, additives, food residues, and contaminants. Most lab studies test clean, single-polymer samples. Fungi that work beautifully on purified polyurethane film may perform very differently when faced with a dirty yogurt container.
End products: Degradation does not always mean the plastic disappears cleanly. When Parengyodontium album mineralized UV-treated PE, most of the carbon was converted to CO₂, with only minor incorporation into fungal biomass.³ Converting plastic waste to carbon dioxide trades one environmental problem for another unless the system is carefully managed.
Safety: Some of the most effective plastic-degrading species, including Aspergillus fumigatus and Fusarium oxysporum, are also human pathogens. Any open-environment deployment would need to account for biosafety risks.

Researchers have proposed more detailed in situ research programs to better understand what actually happens when fungi encounter plastic in natural settings, including tracking changes in polymer structure, mass loss, and enzymatic gene expression in real environments rather than sterile petri dishes.¹ Until those studies mature, the translation from lab to landfill will remain largely speculative.

Could Fungi Turn Plastic Into Something Valuable

The most economically interesting angle may not be making plastic disappear but using fungi to convert plastic waste into useful products. One approach under investigation is using fungi to transform depolymerized plastic into microbial protein, essentially growing fungal biomass on plastic-derived carbon for use as animal feed or industrial feedstock. A life-cycle and techno-economic analysis of this concept found that, at least under certain operating conditions, fungal synthesis from plastic waste can be economically viable, though mechanical recycling still looked more favorable in straight economic and carbon-emission comparisons.¹²

The appeal of this upcycling approach is that it gives the process a revenue stream. Simply breaking plastic down into CO₂ or inert fragments has no product to sell. Growing fungal biomass, or extracting specific biochemicals from it, creates a tangible output that could offset the cost of processing. Whether the economics work at scale remains to be seen, but the concept shifts the framing from “waste disposal” to “biorefinery.”

Agricultural Mulch Films as a Near-Term Target

If there is one area where fungal plastic degradation might see practical deployment sooner rather than later, it is agricultural mulch films. These thin plastic sheets are used by the billions worldwide to suppress weeds and retain soil moisture, and they are notoriously difficult to collect after harvest. Fragments accumulate in agricultural soils, reducing crop yields over time.

Because mulch films are thin, have large surface areas, and are already partially degraded by sun exposure during the growing season, they are far more amenable to biological attack than thick, dense packaging. Research has tested multiple microbial treatments on mulch-grade LDPE. Under carbon-free media conditions, an Aspergillus-only fungal consortium achieved about 3.7% weight loss of commercial LDPE mulch film over 180 days, with measurable changes to the polymer’s molecular weight and chemical surface structure.¹⁰ That rate is still slow in absolute terms, but in a farm-soil context where the alternative is permanent accumulation, even gradual degradation over a few years could prevent long-term damage.

Biodegradable mulch films made from blends of PBAT and polylactic acid are already on the market as replacements for conventional PE films. These materials degrade faster with microbial help, and fungal treatments could accelerate their breakdown further in the soil after use. This particular niche, thin films, partly weathered, sitting in biologically active soil, plays to every strength that fungal plastic degradation currently has. It may be the first application where the biology meets the engineering requirements without needing a breakthrough.

1
PubMed Central. A Review of the Fungi That Degrade Plastic
2
PubMed Central. Marine fungi degrade plastic and can be conditioned to do it faster
3
PubMed. Biodegradation of polyethylene by the marine fungus Parengyodontium album
4
PubMed Central. Fungal Enzymes Involved in Plastics Biodegradation
5
PubMed. Biodegradation of plastics by white-rot fungi: A review
6
PubMed Central. Biodegradation of Polyester Polyurethane by Endophytic Fungi
7
PubMed Central. Breaking Down Linear Low-Density Polyethylene (LLDPE) Using Fungal Mycelium (Part A)
8
PubMed. Degradation of polypropylene by fungi Coniochaeta hoffmannii and Pleurostoma richardsiae
9
Jurnal Natural. Biodegradation of Diisobutyl Phthalate using Fungi Plastisphere Isolated from Plastic Waste in Mangrove Kadilangu Area
10
Science of the Total Environment. Harnessing fungi and bacteria to speed up the biodegradation of plastic mulch films
11
PubMed. Construction of versatile plastic-degrading microbial consortia based on ligninolytic microorganisms associated with agricultural waste composting
12
Chemical Engineering Journal. Life cycle assessment and techno-economic analysis of plastic recycling in microbial protein factory