Scientists Find Hope for Plastic Recycling in Superworms that Feed on Styrofoam

Polystyrene is one of the most widely used plastics, but recycling it is challenging, and the vast majority of it ends up in landfills or the oceans, endangering marine life. Packing material, disposable cutlery, and CD cases are some examples of polystyrene products that are commonly used in everyday life.

Researchers at the University of Queensland in Australia, have been studying the larvae of Zophobas Morio darkling beetles. according to a team of scientists, the superworms, eager to consume polystyrene have gut enzymes that may hold the key to increased recycling rates.

Chris Rinke, who led a study that was published in the journal Microbial Genomic, explained that previous reports had shown that tiny waxworms and mealworms had a reputation when it came to eating plastic. Based on this point, the team hypothesized that the much larger superworms can eat even a larger amount. Waxworms and mealworms are also beetle larvae.

Superworms can grow to be two inches long and are bred as a food source for reptiles, and birds. In Thailand and Mexico, superworms are a delicacy for the locals.

Over the course of three weeks, Rinke and his team fed superworms varying diets, including polystyrene foam, also known as styrofoam. Some of the test subjects were fed bran, while some had no food at all.

Their research has shown that superworms can survive on a polystyrene-only diet and even gain weight when compared to a starvation control group. This indicates that the worms can obtain energy from polystyrene consumption.

Despite the fact that the polystyrene-reared superworms completed their life cycle, becoming pupae and then fully developed adult beetles, tests showed a loss of microbial diversity and potential pathogens in their guts.

These findings suggest that, while the bugs can live on polystyrene, it is not a nutritious diet for the insects and has negative health consequences.

The team then used metagenomics to examine the microbial gut community in order to determine which gene-encoded enzymes were used in the plastic degradation.

Bio-upcycling

One possible application of the findings would be to feed superworms food waste or agricultural bioproducts in addition to polystyrene, Phys Org reports.

This, according to Rinke, could be a way to improve worm health while also dealing with the large amount of food waste that persists in Western countries.

While it is possible to breed more superworms for this purpose, he also envisions designing recycling plants that mimic the larvae's behavior. Rinke imagines steps like shredding the plastic in their mouths before digesting it with bacterial enzymes.

The ultimate goal, according to Rinke, is to eliminate superworms from the equation. He now intends to do more research to find the most efficient enzymes and then improve them using enzyme engineering.

In what Rinke hopes will become an economically viable "upcycling" approach, the breakdown products from that reaction could be fed to other microbes to create high-value compounds like bioplastics.

Further Research

The researchers have already applied for a four-year grant that will begin next year, Interesting Engineering reports.

The team plans to functionally verify, express, and characterize these enzymes afterward. If everything goes according to plan, the team may need another two to three years to further optimize these proteins using enzyme engineering. The team will be able to incorporate the findings into the recycling process as a result of this. Rinke adds that they could be looking at a 10-year timeframe for the study.