The Power of Fungi: A Student’s Look at Mushrooms Breaking Down Eco Plastics
Georgia Udall | September 30, 2021
C Smith removing eco cups from bags for measuring.
In the midst of the pandemic, “eco” cups became more and more common as disposable, to-go options. Despite their eco-friendly sounding name, these cups require a special composting process in order to degrade, meaning they often end up in the trash. These cups are a polylactic acid (PLA) plastic, which is a new, biodegradable material made of things like sugarcane and cornstarch.
C Smith, a biology major and senior here at Warren Wilson College (WWC), conducted research through the Natural Science Undergraduate Research Sequence (NSURS), wanting to know whether or not PLA plastics can be broken down by the mycelium of oyster mushrooms. Since fungi are such good decomposers, one of Smith’s goals was to see if it was possible to reduce plastic waste in landfills through fungi.
Smith used Pleurotus ostreatus, or oyster mushrooms, for their study, due to the mushroom’s broad ability to decompose matter through their mycelium, which secretes digestive enzymes and breaks down dead matter to absorb as food.
“I’m focusing on using mycelia, or the mycelium network, which are basically the root system of mushrooms,” said Smith. “I’m targeting the organic compounds in the cups just to see if we can get some degradation.”
To test how these mushrooms broke down the PLA plastic, Smith developed three groups, each containing mycelium and several eco cups, but varying nutrient levels due to the addition of cotton seed and straw. The added nutrients aid in mycelium growth. After leaving the bags in an incubator for ten weeks, Smith removed the cups and measured their amount of weight lost.
At the end of the ten weeks, Smith found weight losses in all three groups, with a 22% mass loss — that’s almost a fourth — in the group with the most added nutrients. This shows that the mycelium are breaking down the eco plastics.
Smith didn’t know much about mushrooms before this project, and it opened their eyes to how much fungi can do.
“I never knew how much power fungi had and how much they could help pretty large issues on the planet right now,” said Smith. “I think acknowledging the power of nature and what it already does for us … it’s amazing.”
Although this study showcased fungi’s ability to aid in waste reduction, there are still better ways to reduce waste as individuals.
“PLA is not necessarily a great alternative, although it does degrade at a faster rate, considering that regular plastics take years on years on years,” said Smith. “I would say just keep bringing your reusable water bottle with you. Don’t rely on eco plastics because they’re not the solution.”
