I heard a lovely, little story the other day of a serendipitous discovery that may well change the world. One day a couple of years ago, Federica Bertocchini was inspecting her beehives. She noticed that she had an infestation of wax worms living amongst her bees. Having pulled a bunch of them out and left them in an old plastic bag for disposal, she later noticed that there were holes in the plastic bag. Bertocchini is a developmental biologist, not an entomologist, but she nonetheless suspected she knew what had happened.
Wax worms are not actually worms, they are the larvae of a small moth called Galleria mellonella. These larvae grow inside beehives and eat the wax found therein. This is bad news for bees but potentially quite good for us. Though not a plastic per se, wax is a polymer with a similar backbone to polyethylene, the plastic that makes up most of global production – including more than a trillion plastic bags per year.
Bertocchini knew she needed expert help and so teamed up with biochemists from the University of Cambridge to deepen the investigation. Further experiments revealed that the addition of wax worms to plastic did, indeed, result in holes; but they needed to find out if the critters were simply chewing through the plastic or actually digesting it somehow. To find out, they smushed up a whole bunch of the larvae to make a kind of wax worm smoothie. They then applied this to plastic and were very pleased to find that the worm paste was still capable of dissolving plastic. This confirmed that the worms were digesting the polyethylene, either by creating an enzyme themselves or through the action of a bacteria that lived in or on the worm.
The group published their work last month and are now busy trying to identify exactly which enzymes are at work. It isn’t practical to imagine that we can use the wax worm to eat away all of our plastic waste, but it could be feasible to cultivate the enzyme that breaks polyethylene down and somehow incorporate that into our recycling strategies. Conversely, this could be a complete dead end, but we won’t know until we look.