Recent findings have shown that enzymes found in the saliva of certain species of wax moth larvae can break down polyethylene, a type of plastic. This came after elaborate testing carried out on the saliva of wax worms. The enzymes discovered were named Demetra and Ceres and were found to be able to break down complex polymers into smaller fragments. It is still being determined how wax worms can achieve this feat. However, speculations indicate that the similarities in the structures of beeswax and polyethylene might explain why wax worms can break down polyethylene.
What is a Wax Moth?
Wax worms are the caterpillars of various wax moth species. They can grow up to three centimetres at adulthood, at which point they would transition to the next stage in their life cycle. Wax moths attack beehives. They are attracted by beeswax’s pollen and feed on bees’ shed skins.
Amateur beekeeper and scientist Federica Bertocchini discovered the moth wax’s ability as she tried to clean up an infested beehive. She packed the wax moth she cleaned into a plastic bag and found holes made by the larvae just a few days after packing the wax worms.
Bertocchini’s initial conclusion was that the wax moth chewed through the bags. Eventually, tests revealed that the polyethylene was oxidized instead. The discovery of the wax moth’s abilities makes this the fastest process of natural degradation of polyethylene ever discovered. Some fungi and bacteria have been found to be able to break down polyethylene. However, this often takes weeks, if not months, to achieve.
How Could This Be Used to Reduce Plastic Waste?
The world suffers from a perennial plastic problem. Plastic materials contain polymers that are non-biodegradable, which means that they survive for many years, causing environmental challenges. Polyethylene, used in packaging food items and groceries because of its non-interference with food products, makes up 30% of all plastic waste.
The discovery of the enzymes Demetra and Ceres is the first step in degrading plastic waste. These enzymes can be mass-produced and used to break apart plastic polymers. The fragments can be broken down by microbes or combined with other elements to make new products.
There appears to be some work to be done in the future. Bertocchini echoed these sentiments and said:
“…the enzymes can be produced in the lab, (and) it is promising for any future applications. This could include use in waste management facilities to degrade collected plastic, and we could imagine its use in the home further down the line. Before we get to this point, however, we need to know more about these enzymes, including the byproducts of plastic oxidation.”
Other Recent Discoveries of Plastic-eating Enzymes
There have been other discoveries of plastic-eating enzymes apart from the latest. These enzymes have mostly been found to be in microbes. For instance, in 2021, research revealed that ocean and soil bacteria are evolving to degrade plastic. Similarly, in 2020 in Japan, a super enzyme that breaks down plastic drink bottles were created by Japanese scientists. The scientists made their model from naturally evolved bugs found in a waste dump but which displayed a remarkable ability to degrade plastic within a short time. Similar other enzymes have been found in leaf compost.