Scientist and amateur beekeeper Federica Bertocchini picked parasitic wax worms from the honeycomb of her beehives and left them sitting in a plastic bag.
When she returned to the bag, it was riddled with holes and many of the worms had escaped.
It was that chance discovery that led her to collaborate with scientists at the University of Cambridge in England to unearth the possibility of using worms to munch through the world’s plastic problem.
The team discovered the wax worm, a caterpillar commercially bred for fishing bait, has the ability to biodegrade polyethylene – a type of plastic used to make shopping bags – at uniquely high speeds.
The degradation rate was extremely fast compared to other discoveries, like plastic-eating bacteria, the study published in Current Biology found.
When the team exposed about 100 wax worms to a plastic shopping bag, holes started to appear after 40 minutes, with a reduction of 92mg after 12 hours.
To compare: plastic-eating bacteria biodegraded plastic at a rate of 0.13mg a day, and it takes 100 to 400 years to degrade polyethylene in landfill.
Analysis showed the wax worms transformed the polyethylene into ethylene glycol, a chemical used to make polyester and anti-freeze.
The team of three scientists said the discovery could lead to a biotechnological approach to plastic pollution.
People around the world use about 1 trillion plastic bags each year, the study said, and more than 45 million tonnes of polyethylene plastics are produced annually.
“The caterpillar produces something that breaks the chemical bond, perhaps in its salivary glands or a symbiotic bacteria in its gut,” said Cambridge University’s Paolo Bombelli said.
“If a single enzyme is responsible for this chemical process, its reproduction on a large scale using biotechnological methods should be achievable.”
Wax has similar chemical structure to plastic
Wax moths lay their eggs inside hives where the wax worms grow on beeswax.
The worms are known for living like parasites in bee colonies and damaging hives by eating their wax comb.
Researchers said breaking down plastic and beeswax required similar types of chemical bonds.
“Wax is a polymer, a sort of natural plastic, and has a chemical structure not dissimilar to polyethylene,” Ms Bertocchini, from the Spanish National Research Council, said.
When the team mashed up the worms and smeared them into plastic they had similar degradation results to when the caterpillar “ate through” the plastic.
“The caterpillars are not just eating the plastic without modifying its chemical make-up. We showed that the polymer chains in polyethylene plastic are actually broken by the wax worms,” Mr Bombelli said.
“The next steps for us will be to try and identify the molecular processes in this reaction and see if we can isolate the enzyme responsible.”