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These hungry superworms happily munch through plastic

A superworm can eat about eight times more than other plastic-ingesting insects.

These hungry superworms happily munch through plastic
[Photo: badahos/iStock, PamWalker68/iStock]
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Recycling seems like a simple cure for our plastic addiction: just take the plastic we have and make it into new items. But problems abound. Current technology mostly creates plastic of a lower quality than it was before, many types of plastic aren’t recyclable at all, and much of the plastic is floating in the ocean, not even in the recycling stream. So it’s vital that we find new ways to break down plastic, and scientists have just discovered one: a superworm that can eat about eight times more than other plastic-ingesting insects like mealworms.

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Superworms are actually beetle larvae, and commonly sold at pet stores as food for reptiles and fish. In a paper recently published by the American Chemical Society, researchers Jiaojie Li, Dae-Hwan Kim, and their team detail how they placed 50 superworms in a chamber with two grams of polystyrene. After 21 days, the superworms had consumed about 70% of the polystyrene.

[Image: Adapted from Environmental Science & Technology 2020]
The key to that digestion comes from a specific strain of Pseudomonas aeruginosa, a bacteria that lives in the gut of that beetle larvae, and an enzyme that that bacteria creates, called erine hydrolase. Kim, a researcher with Daegu Gyeongbuk Institute of Science and Technology, says that the plan is to isolate the enzyme and see if it can dissolve plastic outside of the worm’s gut. “If it is successful, then this enzyme-mediated plastic biodegradation not only could be demonstrated in the laboratory, but also could be applied as a real bio-technique to remove plastics, especially microplastics in nature,” he says in an email.

Scientists already know that mealworms and waxworms eat plastic. What Kim and Li are so excited about with their latest research is the superworms’ ability to eat more, and digest it more quickly. “The size of superworms is larger than other known plastic-ingested worms, 1.5 times of mealworms,” Kim says, “and thus they ingest relatively more polystyrene per day, eight times more than mealworms.” The superworms don’t seem harmed by ingesting this plastic either, Kim says; more than 90% of the superworms survived with only polystyrene given to them as their sole food source over 21 days.

It may seem unrealistic to pit 1.5 to 2-inch long beetle larvae against the immensity of our plastic problem, but Kim says this discovery is an important part of that larger effort. “Our discovery . . . certainly contributes just a tiny small beginning step, and there will be a long way to go to solve the plastic issue in the world,” he says. “But we are very glad to see that our study intrigues the interests and attentions of other scientists, who may want to devote their efforts in future to solve the plastic issue with us together.”