(ORDO NEWS) — Packaging material, disposable tableware, CD cases: Polystyrene is one of the most common types of plastic, but it is not easy to recycle, and the vast majority ends up in landfills or end up in the oceans, where it threatens marine life.
Scientists from the University of Queensland in Australia have found that superworms – the larvae of the dark beetle Zophobas morio – readily feed on this substance, and their intestinal enzymes may be the key to increasing the level of processing.
Chris Rinke, leader of the study, whose results were published Thursday in the journal Microbial Genomics, told AFP that previous reports have shown that tiny wax and mealworms (which are also beetle larvae) have a good track record when it comes to eating plastic. “So we assumed that much larger superworms could eat even more.”
Superworms grow up to two inches (five centimeters) and are bred as a food source for reptiles and birds and even humans in countries such as Thailand and Mexico.
Rinke and his team fed the superworms various diets for three weeks: some were given styrofoam, commonly known as Styrofoam, others were given bran, and still others were not fed at all.
“We have confirmed that superworms can survive on only polystyrene and even gain a little weight – compared to a starving control group – which suggests that the worms can get energy from eating polystyrene,” he said.
Although the polystyrene-grown superworms completed their life cycle as pupae and then fully grown beetles, analyzes showed a loss of microbial diversity in their gut and potential pathogens.
These results suggested that although the beetles can survive on polystyrene, it is not a nutritious food and affects their health.
Next, the team used metagenomics to analyze the gut microbial community and determine which gene-encoded enzymes are involved in plastic degradation.
One way to apply the findings could be to provide the superworms with food waste or agricultural bio-products for consumption along with polystyrene.
“This could be a way to improve the health of worms and tackle the problem of large amounts of food waste in Western countries,” says Rinke.
But while breeding more worms for this purpose is possible, he suggests another route: setting up processing plants that mimic the work of larvae, which first grind up plastic in their mouths and then digest it with the help of bacterial enzymes.
“Ultimately, we want to take superworms out of the equation,” he said, and now he plans to do more research to find the most efficient enzymes and then improve them with enzyme engineering.
The decay products resulting from this reaction could then be fed to other microbes to create high-value compounds such as bioplastics, which he hopes will be a cost-effective approach to “recycling”.
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