Study challenges assertion that mealworms break down polystyrene

The capability of mealworms to digest and break down plastics has been challenged in a study led by researchers from The University of Western Australia.

The study, led by Ph.D. student Zahra Tahroudi and published in RSC Sustainability, was co-authored by Dr. Georg Fritz and Professor Rob Atkin, from UWA’s School of Molecular Sciences, in collaboration with Dr. Jitendra Joshi from Woodside Energy.

“Previously it has been thought that mealworms could be used to help break down expanded polystyrene, a plastic foam notorious for its environmental persistence,” Dr. Fritz said.

“We found evidence that challenges this assertion and underscores the need for alternative strategies to address polystyrene pollution.”

By controlling variables such as cannibalism and differentiating between pure and commercial polystyrene foam, the study found that mealworms do not chemically degrade the plastic.

Researchers found the presence of additives in commercial polystyrene foam had a small effect on biodegrading the plastic, but it came at a cost to the mealworms’ survival and growth.

“The mealworms exhibited significant weight loss and decreased survival when polystyrene was their only food source, paralleling conditions of starvation,” Tahroudi said.

“The minor chemical changes observed in the plastic were not beneficial and, in fact, pointed to the inherent toxicity of this process for the mealworms.”

The findings are important to help address global sustainability goals by creating eco-friendly solutions for reducing plastic waste.

“There is a need for a deeper investigation into more efficient biological and chemical approaches to manage expanded polystyrene waste,” Professor Atkin said.

“We need to understand the limitations of potential biodegradation agents, which is critical to developing comprehensive and practical waste management solutions.”