Hey team, and welcome back to one5c. Wild winter weather is hitting nearly every part of the country, but don’t let that fool you: The heat is, in fact, still on. Analysis from climate scientists at the European Commission crowned 2023 the hottest year on record, with the global average landing at 1.48 degrees Celsius above pre-industrial levels—and some experts warn we’ll blow past the 1.5-degree goal this newsletter is named for as early as this spring.
A lot of you are new to the one5c community, so I’ll take a beat and explain why that potential tipping point doesn’t have us contemplating a name change right now. The mindset involved in keeping the average global temperature increase below 1.5 degrees won’t go kaput even if we do indeed pass it. The drive to do just a little bit better every day will, if anything, be amplified.
That’s as true for taking the bus instead of driving and trading tuna salad for chickpeas as it is for finding ways to evict plastic from our day-to-day. Which brings me to today’s main story: an excerpt from our comprehensive guide to plastic pollution that explores the role microbes might play in curtailing waste. Share it with a mushroom-lover in your life. —Corinne
Can hungry critters gobble up our plastic problems?
By Molly Glick
sciencepics/Shutterstock
Every piece of plastic ever made still exists, technically speaking. A hunk of plastic takes anywhere from 20 to 500 years to break down, but the polymers never truly vanish: They just get smaller and smaller. As this waste keeps piling up, some living solutions—namely plastic-eating mushrooms, bacteria, and insects—are starting to grab headlines. While the research is still fresh, many scientists are hopeful that we could deploy these hungry organisms to improve our troubled waste system.
Here’s what you need to know about plastic-munching microbes, how they work, and what they might mean for the future of plastic waste.
Mushrooms
Microbiologists have found that certain species of fungi—what you might call “plastic-eating mushrooms”—can break down popular materials like polyethylene and polyurethane, the most commonly used plastics in the world.
Out in nature, fungi degrade organic materials like dead plants and animals, which contain structures somewhat like those found in plastic. Specifically, the mushrooms use a group of enzymes to deteriorate lignin, a natural polymer found in the cell walls of most plants; those same enzymes can degrade the long chains of carbon and hydrogen atoms in mass-produced plastics.
Though studies have confirmed that several mushroom species have this ability, the process is slow: In the wild, it can take the fungi days or months to tear down plastic. In order for these hungry ’shrooms to become a reliable part of our recycling process, scientists have to figure out how to speed things up. They’re currently experimenting with applying heat, UV light, and other pre-treatments to hasten the fungi’s natural process.
More about plastic-eating mushrooms
Bacteria
Scientists have pinpointed more than 400 species of bacteria with the potential ability to weaken plastic’s chemical bonds. Like fungi, these microorganisms, including headline-grabbing examples like Ideonella sakaiensis and Rhodococcus ruber, use enzymes to degrade some types of plastics and turn them into simple nutrients.
Some researchers think that microbes have specifically evolved to eat plastic as it’s clogged up their ecosystems on land and at sea. In an analysis of more than 30,000 enzymes that can break down plastic, the polymer-hungry proteins were found in higher concentrations in areas of the ocean with greater plastic pollution.
It’s too early to say if bacteria could help solve our massive ocean plastic crisis, but researchers have made some exciting progress. R. ruber, for example, could help solve a marine mystery: Around 2% of visibly floating plastic may disappear from the ocean’s surface every year, which could be in part due to destruction by bacteria.
More about plastic-eating bacteria
Worms and bugs
Plastic-munching insects such as the larvae of Galleria mellonella, Tenebrio molitor, and Zophobas morio may offer a distinct advantage over other forms of nature-powered deterioration. While researchers have found that degrading plastic with bacteria and fungi works better when they pre-treat the material with UV light and heat, insect larvae work well without any extra leg-up. Some, like G. mellonella, also work quickly: The enzymes they produce have poked holes in polyurethane in as little as 40 minutes.
For G. mellonella, this speed is thanks to its super-powered saliva. But for T. molitor and Z. morio it’s because they literally eat plastic and turn it into energy. Future waste services could use these creative creepy crawlers to shred waste into small pieces before unleashing bacteria or enzymes to turn plastics back into their building blocks. Still, the molecular biologists studying these ravenous insects say it would likely be more efficient and cost-effective to replicate their skills with machinery and lab-created enzymes. But even this option probably won’t come anytime soon, and could be far costlier than common waste processing methods today.
More about plastic-eating worms and bugs
So, what can we do in the meantime?
Use less plastic. Even the most common and most advanced disposal and recycling methods already out there are no match for the plastic that already exists. According to the Organisation for Economic Co-operation and Development, only 9% of plastic gets recycled and 22% ends up in the environment. Because of that, it’s best to think of polymer-hungry microorganisms as a means to address the plastic pollution that already exists, as opposed to a way to dispose of future plastics.
So while the scientists figure out the next steps with these mushrooms, bacteria, and insects, you should keep swapping single-use products for reusable ones and avoid things like microbeads and excessive packaging. And when you can’t shun plastic entirely, ensure as much as possible makes it into the recycling bin.
More on reducing plastic waste
Molly Glick writes about health, science, and the future. They’re a graduate of The Medill School at Northwestern University, where they studied journalism and environmental policy, and have contributed to Inverse, Discover, and Popular Science, among other publications.