The saliva of a butterfly larva capable of rapidly degrading certain plastics, such as polyethylene, to the point of being used in recycling centers? An improbable recycling solution that has its source in the garden of a Spanish researcher, who published, with her team, her work in early October in the journal Nature.
The amateur beekeeper spots these larvae by cleaning wax combs in her hives. When she puts Galleria mellonella, nicknamed the wax moth, in plastic bags, she notices that they poke small holes in themselves. She and her team from the Margarita Salas Center for Biological Studies in Madrid then provided proof that it was indeed the saliva of these waxworms that degraded the plastic. We are then in 2017.
Five years later, the latest work details the chemical process of this saliva. The researchers show, through laboratory tests, that it is precisely two enzymes in saliva that succeed in the feat of oxidizing plastic at room temperature and after only a few hours. Normally, this oxidation process only occurs at high temperatures or after long exposure to sunlight, but it takes years.
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To accelerate this process, international research has been working on enzymes for more than ten years and this chemical recycling has already been successful. But here, according to these Spanish researchers, these waxworm enzymes are to this day “animal enzymes with the world’s fastest plastic oxidation capacity.”
It will still take a lot of experimentation, but these researchers fully imagine that these insect saliva enzymes could be integrated, for example, into liquid solutions to spray plastic in the waste collection center and accelerate their degradation. And in the meantime, there is still an urgent need to rethink our use of packaging, since in France we only recycle 30% of plastic. Only 10% globally.