Between the ever-growing Great Pacific Garbage Patch, the news that over 90% of plastic isn't recycled, and the likely state of your personal trash can, it's clear that the world has a plastic problem.
Scientists around the world have continued to discover different types of fungus that can degrade specific types of plastic.
We now have 150 million tons of plastic in our oceans, according to estimates; by 2050, there could be more plastic than fish. And every new batch of trash compounds the issue: Plastic is notorious for its longevity and resistance to natural degradation.
Enter the humble mushroom. In 2011, Yale students made headlines with the discovery of a fungus in Ecuador, Pestalotiopsis microspora, that has the ability to digest and break down polyurethane plastic, even in an air-free (anaerobic) environment—which might even make it effective at the bottom of landfills. Although the professor who led the research trip cautioned for moderate expectations, there's an undeniable appeal to the idea of a speedier, cleaner, side effect-free, and natural method of disposing of plastic.
A few years later, this particular application for fungus got a jolt of publicity from designer Katharina Unger, of LIVIN Studio, when she collaborated with the microbiology faculty at Utrecht University to create a project called the Fungi Mutarium. They used the mycelium—which is the threadlike, vegetative part of a mushroom—of two very common types of edible mushrooms, Pleurotus ostreatus (Oyster mushrooms) and Schizophyllum commune (Split gill mushrooms). Over the course of a few months, the fungi fully degraded small pieces of plastic while growing around pods of edible agar. The result? In place of plastic, a small mycelium snack.
Other researchers have continued to tackle the subject. In 2017, scientist Sehroon Khan and his research team at the World Agroforestry Centre in Kunming, China discovered another biodegrading fungus in a landfill in Islamabad, Pakistan: Aspergillus tubingensis, which turns out to be capable of colonizing polyester polyurethane (PU) and breaking it down it into smaller pieces within the span of two months. (PU often shows up in the form of packing foam—the kind of thing you might find cushioning a microwave or a new TV.)
Utrecht University has continued its research, and scientists around the world have continued to discover different types of fungus that can degrade different, specific types of plastic. Khan and his team alone have discovered around 50 more species since 2017. They are currently working on finding the optimal conditions of temperature and environment for each strain of fungus to do its work.
Their biggest problem is perhaps the most common obstacle in innovative scientific research: Cash. "We are developing these things for large-scale," Khan says. "But [it] needs a lot of funding to get to the real application of plastic waste." They plan to apply for a patent soon and to publish three new articles about their most recent research, which might help boost interest and secure more grants.
Is there a way to get the fungi to work faster and to process bigger batches?
Khan's team is working on the breakdown process at this point, but researchers who want to continue in Unger's model of an edible end product also need to figure out how to efficiently and properly prepare the plastic input. "The fungi is sensitive to infection from bacteria," Unger says—which could turn it into a destructive mold. "This is a challenge for industrialization—[the] sterilization of the materials, and making the fungi resistant, strong, and faster-growing, to allow for a commercial process."
Whether it's Khan's polyurethane-chomping fungus or the edible agar pods from the Fungi Mutarium, the biggest question is still about scale. Both projects took several months to fully degrade a small amount of plastic. That's much shorter than plastic's normal lifespan, but still won't be enough to keep up with the global production of plastic. Is there a way to get the fungi to work faster and to process bigger batches?
We'd also need to figure out where these plastic recyclers would live. Could individuals keep a small compost-like heap, feeding in their own plastic and harvesting the mushrooms? Or could this be a replacement for local recycling centers?
There are still only these few small experiments for reference. But taken together, they suggest a fascinating future for waste disposal: An army of mycelium chewing quietly and methodically through our plastic bags and foam coffee cups—and potentially even creating a new food source along the way. We could have our trash and eat it, too.