Common barley bugs can eat plastic waste, which is expected to bring new ways of recycling waste

In a study published in the journal Microbial Genomics, researchers at the University of Queensland in Australia have found that the common barley bug (Zophobas morio, also known as “super crocodile”) can be found in its gut with the help of a bacterial enzyme Phagocytosis polystyrene. This polystyrene ‘appetite’ worm could be the key to the mass recycling of plastic. Scientists hope this “upgraded” biological cycle will lead to new ways of recycling plastic waste, thereby reducing the number of landfills.

Dr Chris Link, from the University of Queensland’s School of Chemistry and Molecular Biosciences, and his team fed barley worms different diets over a 3-week period: some of them polystyrene foam, some of the bran, and Others have fasted.

“We found that barley worms that were fed only polystyrene not only survived, they even gained a little weight,” Dr Link said. This suggests that barley worms can obtain energy from polystyrene, likely in their guts with the help of microbes.

Using metagenomics techniques, the researchers identified several encoded enzymes capable of degrading polystyrene and styrene. Their long-term goal is to engineer enzymes to degrade plastic waste in recycling plants through mechanical shredding and biological enzymatic degradation.

“The barley worm is like a small recycling factory, shredding polystyrene with its mouth and ‘feeding’ it to the bacteria in the gut,” Dr Link said. “The breakdown products from this reaction can be used by other microorganisms to make high-value compounds, such as bioplastics.”

The researchers say their goal is to grow the barley bug’s gut bacteria in the lab and further test its ability to degrade polystyrene, and then figure out how to scale up the process to the level needed at recycling sites.