Accident leads to discovery of plastic eating worms

Many of the world’s greatest scientific breakthroughs happened in laboratories, but every so often, curious discoveries are fueled by chance. A recent example of such a discovery — caterpillars who can chew and potentially digest plastic — might help eat away the tons of plastic waste in landfills all over the earth which would otherwise stay put for centuries or more.

Biologist Federica Bertocchini was tending her beehives at home when she

she came upon greater wax moth caterpillars — waxworms, to be more precise, which are known for being highly destructive to beehives as they chew through the wax that holds hives together.

In an effort to save her hives, Bertocchini removed the waxworms and placed them in a plastic bag, only to later discover holes in the bag and caterpillars missing. According to The Atlantic, as she realized that the worms had eaten their way out of the bag, Bertocchini wondered: “Were the waxworms actually digesting the plastic?”

Bertocchini decided to officially investigate the efficiency of waxworms in breaking down plastic in a collaborative study with University of Cambridge biochemists Paolo Bombelli and Christopher Howe.

Bombelli and Howe “pointed out that, like beeswax, many plastics are held together by structures called methylene bridges (molecular units consisting of one carbon and two hydrogen atoms, with the carbon also linked to two other atoms). These bridges are impossible for most organisms to break, which is why plastics based on them are not normally biodegradable, but the team suspected wax-moths had cracked the problem,” according to The Economist.

While greater wax moth caterpillars are not the first organisms suspected to be capable of breaking down plastic, they are the speediest known; while other organisms took weeks or months, waxworms could chew holes through polyethylene plastic bags in 40 minutes, as The Atlantic reports.

Ultimately, according to The Economist, the team of researchers “discovered their caterpillars each ate an average of 2.2 holes, three millimeters across, every hour, in the plastic film. A follow-up test using standard shopping bags weighing just under three grams each found that an individual caterpillar took about 12 hours to consume a milligram of such a bag.”

While Bertocchini, Bombelli and Howe’s work is exciting in the face of a planet filling with plastic, much research needs to be done before waxworms could be used to help break it down. For example, waxworms love to attack beehives, as Bertocchini noticed in the beginning, and the caterpillars could easily abandon plastic and give their full attention to hives if released en masse, along with any number of ecological disruptions, such as the possibility of toxic feces from waxworms. In an interview with The Economist, Bertocchini noted that the ideal goal would be to “identify the enzymes that they [the worms] are using to degrade polyethylene,” in order to potentially “produce it at high-scale rather than using a million worms in a plastic bag.”  

At any rate, innovations for degrading the vast amounts of plastic on the earth are underway, with hopefully more ideas to come soon, be they biological or by another mode.