Wax Worms to the Rescue

They may not be very cute and cuddly, but caterpillars (larvae) of wax moths, also called wax worms, may prove to be some of the most important creatures. In a 2022 study in the journal Nature Communications, the saliva of these wax worms was found to readily degrade the widely-used plastic polyethylene.

Polyethylene is the most commonly produced plastic, accounting for a full 30% of all synthetic plastic production. It can be found in such things as grocery bags, trash bags, food and beverage containers, as well as shampoo and soap bottles. Currently, the main method used to recycle such items is via mechanical recycling, ie. shredding and grinding.

Plastics, like polyethylene, are composed of long polymers which are designed to be hard to break down. When discarded in the environment, they can remain intact for many years. When they do eventually break down, they transform into tiny micro and nano plastic particles that have been found to contaminate some of the remotest places on Earth.

In this study, though, researchers have found that enzymes contained in the saliva of wax worms, who normally feed on the wax used by bees to build honeycomb, are also able to chemically break down polyethylene. This oxidation of the plastic polymer normally would take energy intensive applications of heat or radiation to break down these same chemical bonds, but the wax worm enzymes were able to accomplish the same feat at room temperature.

Using actual wax worms to do the breaking down of polyethylene, though, comes with its own drawback, namely the carbon dioxide they release as a by-product. Thus in the future, if such enzymes are used in the recycling process at an industrial scale, they will be produced synthetically.