It is thanks to their intestinal enzymes that these larvae of the Zophobas morio beetles could hold the key to a higher rate of recycling, according to researchers from the Australian University of Queensland.

Chris Rinke, who led a study published Thursday in the journal Microbial Genomics, told AFP that previous research had shown that the tiny wax and mealworms (which are also beetle larvae) had a good track record. in terms of plastic consumption.

"So we hypothesized that much larger superworms could eat even more," he added.

Superworms grow up to five centimeters and are bred as a food source for reptiles and birds, or even for humans in countries like Thailand and Mexico.

Rinke and his team subjected the superworms to different types of diets for three weeks.

Some received polystyrene, others sound, still others nothing.

Future recycling plants

"We confirmed that super worms could survive on a polystyrene diet alone, and even gain some weight - compared to a starvation control group - suggesting that worms may gain energy by eating. polystyrene," he said.

Handout from the University of Queensland received on June 9, 2022 and showing Zophobas morio beetles Christian Rinke The University of Queensland/AFP

Although the polystyrene-reared superworms completed their life cycle, becoming nymphs and then fully grown adult beetles, testing revealed a loss of microbial diversity in their guts and potential pathogens.

These results suggest that although insects can survive on polystyrene, it is not a nutritious diet and it impacts their health.

Next, the team used a technique called metagenomics to analyze the gut microbial community and find which gene-encoded enzymes were involved in plastic breakdown.

One way to use the results would be to supply superworms with food waste or agricultural bioproducts to consume along with polystyrene.

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

But if it's possible to breed more worms for this purpose, he envisions another path: to create recycling plants that would mimic what the larvae do, which is to first shred the plastic and then dispose.

"Ultimately, we want to remove superworms from the equation," explained the researcher, who now plans more research aimed at finding the most effective enzymes and then further improving them through enzyme engineering.

© 2022 AFP