Plastic eating fungi pop up in the news and then disappear faster than an Inky Cap disintegrating in your front yard. But what are they? How do they work? And if they could really help our planet’s plastic pollution problem, why don’t we actively use them in our day-to-day lives?
The answer is complicated as I learned researching this article, but the research is also nascent, growing every day as universities and citizen scientists continue to experiment and learn about these fascinating fungi. While mushrooms may not be a complete solution to plastic pollution, it’s remarkable how recently plastic was invented and introduced into our environment and how rapidly fungi have adapted to use it as a food source.
That’s why we’re going to be diving deep in the field of “Mycoremediation” over the next few months here at InoculateTheWorld—the use of fungi to remediate or clean up environmental issues. Because we want to know exactly how mushrooms can help clean up our planet, and what’s holding them back from being used more frequently.
What are Plastic Eating Fungi?
Broadly speaking, fungi are the decomposers in our ecosystem. Different types of fungi evolved to consume different organic materials (hence, wood-lovers, coir-lovers, dung-lovers, etc). Many fungi evolved to break down highly complex organic molecules such as lignin, a polymer that makes wood stiff and hard inorganic materials like rock. Fungi are able to digest such complex materials because they produce enzymes that break them down into simple molecules that they can then absorb.
It’s also important to understand what makes up plastic. Basically, they are chemically complex petroleum products that don’t break down very well on their own and linger in our environment, often causing harm through forever chemicals like PFAS.
Fungi need a carbon source to eat, but luckily plastic can serve as that source. According to a 2022 study, the first step in the myco-digestion process is “weakening of the polymers’ structure.” That means certain fungi can physically change the shape or surface of a plastic by making it more porous or changing the pH of the surrounding environment. Then, the plastic is more accessible for all kinds of microbes to degrade it further. After that, the fungi employs “depolymerization” where the enzymes use the broken down, shorter chains and turn them into water and CO2 or methane.
This means that plastic eating fungi are not just shredding the plastic into smaller pieces, but digesting it into less harmful chemical components. What’s more, numerous studies speak to different fungus’ abilities to remediate PFAS, one of the most concerning forever chemicals.
As more and more types of fungi and microbes are being discovered, scientific innovation can help enhance these discoveries to make the plastic eating mushrooms more effective. Dr. Irina Druzhinina, a key researcher in the field of mycoremediation told Phys.org:
“We have no doubt that microbes will figure out ways to effectively degrade plastic, but this may take thousands of years if we leave nature to run its course. That is why our task is to utilize the knowledge we already possess of microbial biology, to speed up and direct the evolution of microbes and their individual genes to do the job now.”
Species of Plastic-Eating Mushrooms
In recent decades, several species have been discovered and isolated for their plastic eating potential, but it’s more accurate to say that specific species of fungi can eat specific plastic polymers. There’s not going to be a single fungi that can eat everything encompassed by the category of “plastics” so it’s helpful to understand the different species that have been discovered and what types of plastics they target in our environment.
Aspergillaceae family
Several species under the Aspergillaceae family have shown promise for mycoremediation of plastic. Researchers at the University of Sydney found that Aspergillus terreus, as well as another fungus called Engyodontium album were able to degrade polypropylene, a common plastic used in packaging and textiles. Another species, Aspergillus tubingensis, was found to degrade polyurethane. Researchers discovered this fungus breaking down plastic at a landfill, and decided to look into it further in controlled experiments.
Discoveries like this can help narrow the focus of lab research to make fungi more effective. Researchers look into the optimal growing conditions for mycelium and study the speeds they are able to degrade plastics. They also uncover which enzymes produced by the fungi are responsible for plastic degradation. This is helpful because they can figure out whether the enzymes need some other element to function—oxygen for example—and make corresponding adjustments to speed up plastic degradation.
Pestalotiopsis microspora
One of the most commonly cited plastic eating fungi, Pestalotiopsis microspora, was discovered in the Amazon rainforest. P. microspora is unique because it can grow in anaerobic conditions, meaning it’s able to grow without oxygen. This makes it particularly useful for mycormediation conditions in real life because not everywhere we need to remediate plastic pollution is going to have a perfect, oxygen-rich environment.
Pestalotiopsis microspora has gained traction among accredited researchers and citizen scientists alike as people try to approach the plastic pollution crisis. Numerous examples of research in universities is promising, and there are already citizen scientists experimenting with it as well.
Although P. microspora evolved to decompose materials in the Amazon forest floor, it has been found to feed off of polyurethane, which is a common plastic polymer found in just about anything you can think of, from insulation and furniture to clothing. Although addressing polyurethane in our environment is crucial, it’s important to note that it actually only makes up about 6% of global plastic pollution, and it’s less toxic compared to some of the other plastics out there.
Parengyodontium album
Another promising candidate for mycoremediation is Parengyodontium album, which breaks down polyethylene, the most commonly produced plastic and the most abundant plastic polluting our oceans.
Parengyodontium album is an extremely common and voracious fungus found on everyday objects. It’s even known to cause problems, like eating through cultural heritage objects. On a more positive note, the fungus’ appetite for destruction is helpful for our plastic problem especially within our oceans, as it’s been found to break down marine plastic quite efficiently. Once polyethylene products are exposed to UV light (i.e. sunlight from floating on the ocean’s surface) the fungus can start to break down these polymers. Researchers expect that P. album is not the only fungus of its kind, and more fungi with these properties will be found in the future.
Oyster Mushrooms and Split Gill Mushrooms
Surprisingly, some fungi capable of digesting plastic are relatively common species, such as Pleurotus ostreatus (a type of Oyster mushroom) and Schizophyllum commune (Split-gill mushrooms).
In addition to accredited research around these fungi, a number of inspiring art and design projects have sprung up around their plastic eating potential. They are a great way to encourage community use and involvement, and serve as a way forward for people to take efforts against plastic pollution beyond just reducing their personal plastic consumption. Citizen scientists are making use of these fungi in their own lives, and you can find posts on Reddit on their progress, like this thread on Blue Oyster mushrooms.
Potential Uses of Mushrooms That Eat Plastic
Given these different examples of plastic eating fungi, we can already see a few different applications, from highly controlled lab contexts to individualized experiments using one’s own personal plastic waste. But how do we make sense of these different options and their real potential in our fight against plastic pollution?
Industrial Plastic Processing Facilities
The ultimate goal for many prominent researchers is to figure out how to make these fungi effective on an industrial level. Much of the lab work happens within a super controlled experimental context with stable temperatures, pH levels, and lighting, and without any competitors or organisms the fungus might run into in a ‘real-life’ ecosystem. Many studies aim to isolate or selectively breed the useful genes and enzymes to make their plastic eating capabilities more efficient by manipulating the fungus and its environment.
When researchers conclude what works through such methodical trials, they can isolate these practices within processing plants where plastic gets sent and undergoes hyper-specific procedures to break it down as quickly as possible.
Field Study: Plastic Eating Fungi in the Ocean
Other conservationists believe in studying the issue in its imperfect and varied field environment. Instead of handling the issue at a processing plant, the field study approach may introduce a new fungus known to interact with contaminants directly to an environment.
Other field studies approach the problem by encouraging the growth of fungi already active and adapted to a specific environment that may already be feeding from some of the plastic there. Much of the research around this is focused on the ocean, where massive amounts of plastic build up. This is exactly how prominent research on Parengyodontium album took shape, as scholars observed the fungus interacting with certain types of plastic and studied its full effects.
The field study approach also encompasses on-the-ground, community involved projects. Dr. Danielle Stevenson pioneered several community-involved fungi initiatives, including household experiments to break down diapers (which would otherwise sit in the landfill indefinitely). In an interview, Dr. Stevenson said, “The scale of the problem means we need scalable solutions,” meaning that community household experiments like these are crucial to tackling the issue.
Why Aren’t We Using More Plastic Eating Fungi?
Despite the promising research in the field of mycoremediation, and its broad range of applications, skepticism pervades the topic of plastic eating fungi. The attitude tends to be that not enough is happening in this sphere at the moment for it to really make a difference.
One major issue is the sheer volume of plastics in our environment and their location in the ocean. The speed of fungi’s ability to degrade plastic and the rate at which we produce it does not inspire confidence compared to the volume of plastic. There’s often a sense that unless a solution quickly reverses a problem and allows us to maintain the status quo in every other way, it’s not a good solution. The reality is that nothing happens overnight and any action we take will need to be paired with a reduction in our plastic consumption.
Most skeptics will say that the surface decomposition of plastic doesn’t result in meaningful reduction in plastic, and that these fungi are too slow at breaking plastics down to make a real difference. It’s important to remember that the early stage trials happening now are just the beginning, and through these trials, fungi’s ability to eat plastic will likely become more efficient in the coming years. The enthusiasm behind plastic eating mushrooms wanes when people realize that the fungi can’t break things down overnight. This leads to less commercial investment in these projects, which reinforces the uncertainty around their efficiency and investment value.
Plastic Eating Fungi Present a Promising Solution
Even though it’s a challenge that there’s not one be-all-end-all mushroom that eats all kinds of plastics quickly, it doesn’t mean there’s not a solution here. Most skeptics assume that individuals aren’t smart or driven enough to take the complex needs of each species into consideration, suggesting that it’s not feasible for regular people to experiment with them because mushrooms are so finicky.
Yet, the ITW community is filled with DIY mycologists, citizen scientists, and people who enjoy a good challenge. So, we believe it may be feasible if you enjoy the process of experimentation like this. These experiments could be a fun way to spend a Saturday, reduce your personal waste, and even potentially change the world! We even stock 5 different types of Oyster mushrooms to experiment with, and they’re some of the easiest gourmet mushrooms to grow!
As research advances, the potential for selective breeding and optimized environmental conditions can pave the way for more effective applications for these fungi. Furthermore, these integrating methods into grassroots and community-driven projects will allow people to tackle the problem on a smaller scale, while increasing public engagement around the issue.
Yet, there are even more reasons to be optimistic about these fungi. Dr. Danielle Stevenson told Reality Studies Podcast that mycoremediation is cheaper compared to other methods and not as slow as naysayers often claim. Additionally, there is lots of room for workforce development in bioremediation, which could have huge positive economic impacts as these methods get applied at the scale of the problem.
By embracing innovation in this field and recognizing the role of small-scale citizen science, we can harness the potential of these fungi into a crucial part of our fight against plastic pollution.