Plastics are inexpensive and widely used organic polymers, but their high durability hinders biodegradation. A species of worm with an appetite for polystyrene could be the key to plastic recycling on a mass scale.
Now, researchers at the University of Queensland’s School in Australia have discovered the common Zophobas morio ‘superworm’ can eat through the polystyrene, thanks to a bacterial enzyme in their gut. Their findings offer new insights into plastic biodegradation and could help tackle plastic pollution.
Researchers fed superworms different diets over a three-week period, with some given polystyrene foam, some bran others put on a fasting diet. They found the superworms fed a diet of just polystyrene not only survived but even had marginal weight gains. This suggests the worms can drive energy from the polystyrene, most likely with the help of their gut microbes.
Using a technique called metagenomics, the team identified several encoded enzymes with the ability to degrade polystyrene and styrene. Their long-term goal is to engineer enzymes to degrade plastic waste in recycling 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,” Dr. Rinke from UQ’s School of Chemistry and Molecular Biosciences said. “The breakdown products from this reaction can then be used by other microbes to create high-value compounds such as bioplastics.”
In the next step, researchers aim to grow the gut bacteria in the labs 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,” said Ph.D. candidate Jiarui Sun, co-author of the research.
Dr. Rinke said there are many opportunities for the biodegradation of plastic waste. “Our team is very excited to push the science to make it happen,” he said.