A new study led by the University of Queensland has found that the common Zophobas morio “superworm” is able to eat through polystyrene – a versatile, solid plastic used to make a large variety of consumer products – due to a bacterial enzyme in their gut. This discovery could help scientists engineer enzymes to degrade plastic waste in recycling plants through mechanical shredding followed by enzymatic biodegradation.
The researchers fed superworms different diets over a period of three weeks, with some of them given polystyrene foam, some bran, and others forced to fast.
“We found the superworms fed a diet of just polystyrene not only survived, but even had marginal weight gains,” said study senior author Christian Rinke, an expert in the genomics, ecology, and phylogeny of uncultured microbes. “This suggests the worms can derive energy from the polystyrene, most likely with the help of their gut microbes.”
Dr. Rinke and his team used a technique called metagenomics to identify several encoded enzymes that were able to degrade plastics such as polystyrene and styrene.
“Superworms are like mini recycling plants, shredding the polystyrene with their mouths and then feeding it to the bacteria in their gut. The breakdown products from this reaction can then be used by other microbes to create high-value compounds such as bioplastics,” Dr. Rinke explained.
In future research, the scientists aim to grow these gut bacteria in the laboratory and further test their ability to degrade various types of plastic waste.
“We can then look into how we can upscale this process to a level required for an entire recycling plant,” said study co-author Jiarun Sun, a doctoral student at the University of Queensland. If these initiatives turn out to be successful, plastic recycling on a mass scale could finally be a viable option for reducing plastic pollution.
The study is published in the journal Microbiology Society.