Scientists Found Superworms That Love Eating Styrofoam

Material for packaging, disposable cutlery, and CD cases: Polystyrene is one of the most common types of plastic, but recycling it is difficult, and the great majority of it ends up in landfills or in the seas, endangering marine life.

Superworms - the larvae of Zophobas morio darkling beetles – are eager to eat the material, according to researchers at Australia's University of Queensland, and their stomach enzymes may hold the secret to increased recycling rates.

"We hypothesized that the much larger superworms can eat even more," Chris Rinke, the study's lead author. Previous reports had shown that tiny waxworms and mealworms (which are also beetle larvae) had a good track record when it came to eating plastic.

Superworms, which may reach a length of two inches (five cm), are grown as a food source for reptiles, birds, and even people in Thailand and Mexico.

Over the course of three weeks, Rinke and his colleagues fed superworms several diets, including polystyrene foam, sometimes known as styrofoam, bran, and no food at all.

"We confirmed that superworms can survive on a sole polystyrene diet, and even gain a small amount of weight – compared to a starvation control group – which suggests that the worms can gain energy from eating polystyrene," he added.

Despite the fact that the polystyrene-reared superworms completed their life cycle, becoming pupae and eventually fully fledged adult beetles, testing indicated a reduction of microbial diversity and possible pathogens in their bellies.

These findings revealed that, while the bugs may survive on polystyrene, it is not a healthy diet for them.

The scientists then employed metagenomics to examine the microbial gut population and determine which gene-encoded enzymes were involved in the plastic degradation.


One application of the results would be to feed superworms food waste or agricultural bioproducts in addition to polystyrene.

"This could be a way to improve the health of the worms and to deal with the large amount of food waste in Western countries," said Rinke.

While it is feasible to produce more worms for this purpose, he envisions a different path: developing recycling plants that replicate what the larvae do, which is to shred the plastic in their teeth before digesting it with bacterial enzymes.

"Ultimately, we want to take the superworms out of the equation," he said, adding that he now intends to do additional study focused at identifying the most effective enzymes and then improving them further through enzyme engineering.

In what he thinks will become an economically feasible "upcycling" technique, the breakdown products from that reaction may be given to other bacteria to make high-value chemicals like bioplastics.