The answer to biodegrading plastic may lie in the stomach of a wax worm
In what was an accidental discovery, Federica Bertocchini, a scientist based in Spain, found the key to biodegrading plastic. Bertocchini, a bee hobbyist, was removing the wax worms from a hive and placed them in a plastic bag overnight. The next day, she noticed a slightly disgusting but intriguing discovery, “they were all crawling around my place and the plastic bag was riddled with holes.”
The curious scientist and her team wanted to test if and how the creatures were chemically biodegrading plastic. To find out, they placed 100 wax worms in polyethylene plastic, a common material used to make plastic bags.
After 12 hours, the plastic had noticeably degraded. The results, shown in Figure 1A/B, show that the wax worms ate through the plastic. The scientists ruled out that the wax worms were mechanically breaking the plastic by smearing homogenized wax worms guts on a plastic bag; they noticed a 13% reduction in mass when doing so. “So it had to be something chemical that was going on and not a physical breakdown,” one of the scientists, Christopher Howe, of the University of Cambridge told NPR.
The scientists conducted further tests and found that the plastic was degraded to ethylene glycol, a reagent commonly used in antifreeze. Howe had this to say, “It’s not itself a very exciting product, from our point of view, but what matters is that we’re able to turn the plastic into something else.” The study’s results, published in Cell, illuminates new enzymes that biodegrade plastic. Scientists know the byproduct of breaking down plastic, but it is still unknown how it is degraded to ethylene glycol. In fact, it may not be the creatures themselves degrading the plastic but a bacterium found in the gut of the worm.
This wouldn’t be the first time bacteria have been found to degrade plastic. Bacteria found in the Indian Meal Moth, Plodia interpunctella, can break down polyethylene but at a very slow rate.
Regardless, there is now evidence of a faster enzyme capable of degrading plastic. Now, it is only a matter of time before someone discovers the enzyme found in worms and markets its social use.
With millions of tons of plastic contaminating our oceans, it is the highest source of pollution in the oceans by far. An enzyme that degrades plastic may be the biodegradable solution to our plastic pollution problem, and help decrease further contamination.
Cover picture source: West Coast Oceans