This Is Plastics: Future of Plastics: Eating Away at Plastic Waste, Part II

Environment

Future of Plastics: Eating Away at Plastic Waste, Part II

This installment of the Future of Plastics series takes a look at the worms actually eating away at plastic waste.

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Continued research into plastics recycling has unearthed a variety of circular innovations, from nanotechnology to plastic-“eating” bacteria like Ideonella sakaiensis. But even before the discovery of these miniscule creatures in 2016, researchers were already studying a different plastic-eating organism—worms!

Plastics offer an alternative diet for mealworms

In 2015, scientists at Stanford University found that Tenebrio molitor, the larvae of the yellow darkling beetle also known as the “mealworm,” can survive on a diet solely of polystyrene, the type of plastic most commonly known as Styrofoam. Microorganisms and enzymes in the mealworms’ intestines biodegrade plastics during digestion, converting half of the material into carbon dioxide and the other half into organic waste, just as they would with other food sources. Specifically, the researchers found that the diet was just as healthy as the worms’ standard diet of various grains and flour—and that their waste could be safe for further use, such as composting or soil for crops.

A separate team of researchers from Australia’s University of Queensland had similar a breakthrough in 2022 when they discovered that the larvae of another species of darkling beetle—Zophobas morio, also known as the “superworm”—could also survive solely on a polystyrene diet. This particular wormwas found to have gut enzymes that digest polystyrene and produce only organic waste as a result. Like the Stanford research, the plastic diet proved to be healthy for the worms, and lead researcher Christian Rinke calls it “a new, arguably, better, environmentally friendly way” to break down the plastics.

Gut enzymes could lead to larger plastic waste breakthroughs

Researchers around the world view these worms as a unique organic end-of-life opportunity for polystyrene. Because the material is frequently used for food and drink containers, it is often unable to be recycled with current technology due to food contamination. However, food contamination is not a problem for the “worm solution,” which presents an ideal disposal method. Identifying recycling processes for this popular plastic has the potential to divert a third of global waste from landfills, while contributing to local ecosystems through the feeding and waste products of these worms.

Currently, scientific focus is on identifying the specific enzyme that allow these darkling beetle larvae to effectively break down the polystyrene, so the process can be recreated in an industrial setting and deployed at scale. Researchers hope to isolate the enzyme for use in liquid solutions at recycling centers, so plastics can be digested into inputs for new product creation without the need for live worms. While this research is still in its infancy, the technology could be commercially viable in the next five to ten years. In the meantime, there is also a focus on creating  “do-it-yourself” composting kits for consumers to break down the material at home in a backyard worm farm, making this environmentally friendly recycling process accessible regardless of recycling center proximity.

An additional improvement to plastic circularity

The ongoing worm and enzyme research adds to a growing list of breakthroughs that are improving and increasing circular opportunities for plastics. From interventions at the molecular level to federal policies promoting recycling solutions, the plastics industry is continuously innovating end-of-life options for plastics to ensure the material continues to benefit consumers in new uses and products.

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