“Superworms” that eat polystyrene might help plastic pollution problem

Researchers may have found an extremely old solution to help solve part of the relatively new problem of plastic waste.

As reported in a recent article in The Scientist, an online scientific publication produced by science writer Nayanah Siva, researchers in Beijing have discovered that “scavenger” worms – a species that has existed for over 100 million years, and once fed off the bones of dinosaurs – will eat Styrofoam, which is one of the most difficult plastic materials to biodegrade.

Not only were the worms – also known as superworms – able to eat the material as their sole diet, but the researchers found that their gut microbiota degraded the polystyrene and converted the complex substance into carbon dioxide, according to findings in a paper by Yu Yang, Jialei Wang, and Mengli Xia, published in Science of the Total Environment. “Superworms can eat and live well with Styrofoam as sole diet,” they reported in conclusion.

The research – which builds on previous studies that found wax worms and mealworms were also able to eat plastic – opens up the possibility of harnessing their abilities to help tackle the issue of plastic pollution, the researchers said.

Siva quotes Anja Malawi Brandon, a PhD candidate at Stanford University who was not involved in this study. “A lot of these insects, such as superworms or mealworms…developed over time to be scavengers and eat and break down all sorts of materials that they find, including wood-based material,” Brandon said, which is difficult to degrade.

In her article, Siva noted several years ago researchers from the School of Life Science, Beijing Institute of Technology in China studied larvae of the mealworm beetle and reported that the worms were able to degrade and mineralize Styrofoam, confirming that the gut bacteria broke down the polystyrene.

In their latest project, the team turned to superworms to see if these worms were also capable of digesting and breaking down Styrofoam – and found that the average consumption of the material was about 0.58 mg per day, which was four times more than what the mealworms had eaten; and that the superworms had converted 36.7 per cent of the ingested Styrofoam into carbon dioxide. “This new finding…indicates that the gut microbiota of superworms would be a novel bioresource for pursuit of plastic-degrading enzymes,” the team wrote.

Additionally, Siva writes, the team of researchers “found that the worms eating HBCD-laden polystyrene were just as healthy as the worms that had a normal diet, and the shrimp that ate the polystyrene-fed worms were healthy, as well. [Brandon] and her colleagues were shocked by the results, as they had suspected that chemicals such as HBCD would bioaccumulate in the shrimp.”

These findings dovetail with a recent study by Brandon and her colleagues at Stanford University, which found that “mealworms were able to eat polystyrene that included a common toxic flame retardant, hexobromocyclododecane (HBCD), and still serve as safe food for other animals.”

More research remains to be done, but it’s not impossible that superworms could eat their way towards our planet becoming a little less littered with Styrofoam.