Hungry for plastics: Polystyrene eating worm for “mass-scale” plastic recycling

10 Jun 2022 --- Researchers at the University of Queensland, Australia, have discovered a species of worm with an appetite for polystyrene, highlighting they could be the key to plastic recycling on a mass-scale. The common Zophobas morio “superworm” can eat through polystyrene, thanks to a bacterial enzyme in its gut.

Dr. Chris Rinke and his team from the University of Queensland’s School of Chemistry and Molecular Biosciences fed superworms different diets over a three-week period, with some given polystyrene foam, some bran and others put on a fasting diet.

“We found the superworms fed a diet of just polystyrene not only survived but even had marginal weight gains,” says Dr. Rinke. “This suggests the worms can derive energy from the polystyrene, most likely with the help of their gut microbes.”

Dr. Chris Rinke and his team from the University of Queensland fed superworms different diets over a three-week period.“Mini recycling plants”
The researchers say they used a technique called metagenomics to find several encoded enzymes with the ability to degrade polystyrene and styrene.

The long-term goal is to engineer enzymes to degrade plastic waste in recycling plants through mechanical shredding, followed by enzymatic biodegradation.

“Superworms are like mini recycling plants, shredding the polystyrene with their mouths and then feeding it to the bacteria in their gut,” explains Dr. Rinke. “The breakdown products from this reaction can then be used by other microbes to create high-value compounds such as bioplastics.”

Biodegradation of plastic waste
Researchers hope the bio-upcycling will incentivize plastic waste recycling and reduce landfill.

Co-author of the study, Ph.D. candidate Jiarui Sun, says the researchers aim to grow the gut bacteria in the lab and further test its ability to degrade polystyrene.

“We can then look into how we can upscale this process to a level required for an entire recycling plant,” adds Sun.

The long-term goal is to engineer enzymes to degrade plastic waste in recycling plants through mechanical shredding, followed by enzymatic biodegradation.Dr. Rinke highlights that there are many opportunities for the biodegradation of plastic waste.

“Our team is very excited to push the science to make it happen,” he concludes.

More plastic-eating news
Last year, researchers at Chalmers University of Technology, Sweden, discovered the global environment is naturally producing an increasing number of microbial enzymes that can degrade plastic waste as pollution levels continue to rise.

The researchers said the rate of enzymatic degradation is rising in correlation with local levels of plastic pollution, showing a remarkable sign of how the environment reacts to the damage caused by waste.

Staying on track of this research development, PackagingInsights later sat down with Aleksej Zelezniak, associate professor at Chalmers University, Sweden, to discuss how these discoveries could be utilized by the packaging and waste management industries to tackle pollution.

Meanwhile, researchers from the US-based University of Montana and the University of Portsmouth, UK, together discovered an enzyme that has a “remarkable capacity” to break down terephthalate (TPA) – one of the chemical building blocks of PET plastic, which is used primarily to make single-use drinks bottles, clothing and carpets.

By Natalie Schwertheim

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