We have a plastic problem.
You’re doing your part–you’re using paper straws, you’re reusing bags. But so much of this plastic waste has been around for years before you.
Sometimes, it can feel hopeless.
But maybe nature’s throwing us a bone–because now worms can eat plastic.
Galleria Mellonella, Plastic Eater
Galleria mellonella is the scientific name for wax worms. Wax worms look like little maggots, but their repulsive appearance is counterbalanced by their cool ability. They live in beehives and sustain themselves by feeding off the wax in there.
“Since they eat wax, they may have evolved a molecule to break it down,” says Federica Bertocchini. She is a developmental biologist working at the University of Cantabria in Spain. “That molecule,” she adds, “might also work on plastic.” And it did, to a certain extent. Over the course of a night, 100 worms ate 92 milligrams of a standard plastic grocery bag.
You may notice, that’s not a lot. National Geographic has done some math for us. “At this rate,” they explain, “it would take these same 100 worms nearly a month to completely break down an average, 5.5 gram plastic bag.” (1)
What’s The Use, If It Consumes So Little Plastic?
“This study is another milestone discovery for the research on biodegradation of plastics,” according to Wei-Min Wu. He’s an environmental engineer at Stanford University. Back in 2014, he and a Stanford team looked at a different species of wax worm. Interestingly, it, too, ate plastic. However, the resulting byproducts of the worm’s digestion were different. This excites Wu. “There are probably lots of other worm species out there that can degrade plastics,” he says.
However, even though the rates seem long, the 100 worms, 12 hours, 92 milligrams rate is actually faster than other microbes.
Additionally, Chemical and Engineering News says that while certain plastic compounds come apart fairly easily, polyethylene, which is what plastic bags are made of, is notoriously more difficult to break down. This could explain Wu’s undauntedness by the tiny tummies of the worms. (1, 2, 3)
Challenging Federica Bertocchini
Four months after Bertocchini reported that her wax worms were chowing down, scientist Till Opatz from the Johannes Gutenberg University Mainz claimed something different. He said the worms weren’t digesting the plastic–it was a false positive, based on “ground-up caterpillar proteins that stuck to the polyethylene film after washing.”
To support his critique, he and his colleagues smeared pork proteins on plastic–and got similar results to Bertocchini.
Jun Yang, of Beihang University, says that “it’s possible to confirm biochemical polyethylene breakdown with other techniques, including mass measurements, gel permeation chromatography, and infrared and nuclear magnetic resonance spectroscopy.”
Opatz disagrees; he says it’s impossible, using those methods, to tell the difference between contamination and digestion. (3)
Is Eating Plastic Even The Best Idea?
Marine biologist Tracey Mincer says no. “Polyethylene is a high-quality resin that can be up-cycled in many ways and can fetch up to $500 per tonne,” he says. “This is an amazing natural history story and wonderful academic exercise.” However, “it is not a solution for disposing of polyethylene as this is throwing away money.” (1)
