The enzyme that eats plastic waste was widely reported in the news last week. The scientists who accidentally created the mutant enzyme observed that their mutated molecule was better at breaking down Polyethylene Terephthalate (PET) than the naturally occurring molecule that they were experimenting with. We thought we’d take a look at how this breakthrough came about and what implications it has for the future of recycling plastics.
Where did this enzyme come from?
Committed readers of this blog may recall that we wrote about the catchily-named bacterium Ideonella-Sakaiensis 201-F6 in a post about plasticophagic organisms back in 2016. At that time, the micro-organism had only just been discovered in a Japanese rubbish dump and there were high hopes for breeding it and spraying it on the ocean's plastic waste dumps. Fast forward two years and scientists have isolated the enzyme that the bacterium uses to break down the plastic and have started experimenting with it.
What is an enzyme?
An enzyme is an organically produced molecule that acts as a catalyst. A catalyst, for those of you who’ve long put away your GCSE chemistry books, speeds up a chemical reaction without itself being altered by that reaction. Living organisms produce enzymes that help them break large complex molecules into smaller ones that can be digested. This is how digestion works in all organisms including humans.
How does this mutated enzyme break down plastic?
In the case of Ideonella, the enzyme in question looked very similar to enzymes that are used by some bacteria to break down naturally occurring plant polymers. The scientists investigating how the one might have evolved into the other accidentally created an enzyme 20% more efficient at breaking down plastic. Professor John McGeehan, who led the research at the University of Portsmouth, told the Guardian:
“It is a modest improvement – 20% better – but that is not the point. It’s incredible because it tells us that the enzyme is not yet optimised. It gives us scope to use all the technology used in other enzyme development for years and years and make a super-fast enzyme.”
The future of plastic recycling?
Enzyme development – tweaking naturally occurring enzymes to make them more efficient for human applications – is a well understood science. The technique has been developed over many decades in the pursuit of ever more powerful biological washing powders. Applying these optimisation techniques to the Ideonella enzyme could create a super-fast plastic digesting enzyme that breaks PET plastic into its component parts ready to be recycled. Introducing the enzyme into the recycling process would enable PET plastic to be recycled into more PET plastic – negating the need to use oil to make virgin plastics.
At Coda Plastics Ltd, we consider plastic to be a fantastic resource material. We already recycle our own plastics and we even take in plastic from other manufacturers and recycle that. We’ll be keeping a careful eye on developments in this field. If you would like your product developed and manufactured by a company with a responsible approach to plastics recycling, please get in touch. You can call us on +44 1692 501 020 or email firstname.lastname@example.org.
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