Stanford University scientists have shown how mealworms can consume various forms of plastic as well as digesting the toxic plastic additives. Remarkably, there are no ill effects for the mealworm.
In terms of how mealworms can breakdown plastics and associated toxins, this comes down to the bacteria in the gut of the worm, which are capable of biodegradation. Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle.
In studies, the researchers examined polystyrene, which is used for packaging and insulation. The material is expensive to recycle, and it contains the toxic flame retardant hexabromocyclododecane (HBCD). This chemical is thought to have health and environmental impacts, including both endocrine disruption to neurotoxicity. There is talk of banning the use of hexabromocyclododecane in both Europe and the U.S.
Tests using the plastic and mealworms revealed that the worms excrete around half of the polystyrene they consume in the form of degraded fragments and the portion as carbon dioxide. The study also showed that mealworms fed a steady diet of HBCD-containing polystyrene were of equivalent health as those fed a normal diet.
According to lead researcher, Anja Malawi Brandon, the results were surprising: “It’s amazing that mealworms can eat a chemical additive without it building up in their body over time.”
While mealworms reduce the quantity of HBCD they do not completely eliminate it. Mealworm-excreted HBCD still poses an environmental hazard, but the quantity is reduced by around 50 percent, presenting mealworms as a potential partial solution for the global plastic waste crisis.
In terms of what happens to the mealworms afterwards? The worms can be used as a safe, protein-rich feed supplement.
The novel research has been published in the journal Environmental Science & Technology. The research paper is titled “Fate of Hexabromocyclododecane (HBCD), A Common Flame Retardant, In Polystyrene-Degrading Mealworms: Elevated HBCD Levels in Egested Polymer but No Bioaccumulation.”