Plastic Bag Waste in the Oceans
Over three trillion single use plastic bags are produced every year. Much of them find their way into our oceans. A large majority of these bags are made of polyethlene (PE). Polyethylene is a strong plastic that takes decades to break down. But it may be that the lowly wax worm can offer a solution to this massive problem.
Wax worms are commercially grown as food for humans in areas where meat is not readily available. They are used as well as live food for terrarium pets and some birds. However, most people will recognize them as food for captive reptiles such as bearded dragons, geckos, chameleons, turtles and hedgehogs, etc. Additionally, they are used as bait by anglers who refer to them as waxies. They are high in fat content, easy to breed and can survive for weeks at low temperatures.
Greater Wax Moth
However, an accidental discovery may help scientists find a remedy to all that PE waste. Scientist and beekeeper, Federica Bertocchini, from the Institute of Bio-medicine and Biotechnology of Cantabria in Spain was tending her bees in her backyard. She had cleaned out a hive that was infested with wax worms and put the debris in a plastic bag. Shortly after she saw that the plastic bag was full of holes. The wax worms had escaped.
So, were the wax worms just chewing through the plastic bag or were they actually eating it and breaking it down chemically in their guts? Bertocchini and her team decided to test the alternatives. They ground up some wax worms and spread the resulting pulp on a polyethylene bag. The PE bag degraded. Clearly a chemical reaction was going on and not just a physical breakdown.
Polyethylene into Glycol
The wax worm were actually changing the polyethylene into glycol, a liquid. Glycol is an alcohol. Thus the experiment showed that the polyethylene could be broken down into another material.
Enzyme in the Gut of Wax Worms
It is not clear how the wax moth chemically breaks down the plastic. Wax worms like to live in beehives where they survive on wax and honey. Both beeswax and polyethylene have strong carbon bonds. It is possible it is not the worm itself that causes the material to biodegrade but an enzyme in the gut of wax worms..
Another group of scientists at Brandon University in Manitoba, Canada concluded that the micro-organisms in their guts did allow the wax worms to “ingest and metabolize” polyethylene at an impressive rate. Furthermore, the researchers found that wax worms could survive on a sole diet of polyethylene. The scientists dubbed them “plastivores.”
Releasing live wax worms on plastic waste is not a viable solution. Wax worms are pests that like to feed on honey combs endangering bees and the crops and plants bees pollinate. And then what will do we do with all that glycol they might produce? Researchers are looking for ways to harness the gut bacteria to develop products or by-products that can be used to efficiently breakdown plastics. Therefore whole live organisms would not be required.