Scientists have stumbled on a mutant enzyme that could unlock the answer to tackling the global mountain of plastics recycling.
The initial discovery of a microbe in the soil of a Japanese recycling plant which had evolved to eat plastic soda bottles began a journey of discovery.
A team headed up by structural biologist John McGeehan, of the UK’s University of Portsmouth and including researchers from the US Department of Energy’s National Renewable Energy Laboratory have since created a new enzyme, one that breaks down plastics quicker.
The discovery was made as they investigated the crystal structure of PETase – the enzyme that helps the Japanese microbe, Ideonella sakaiensis, break down polyethylene terephthalate plastics.
They examined the internal workings of PETase’s molecular level, using X-rays to generate a 3D model of the enzyme. And also how the mechanism can be improved and speeded up.
Rather than take centuries to break plastics down, the process can be shortened to days, with a clear beginning of the microbe eating the plastics in just 96 hours, as reported in Proceedings of the National Academy of Sciences.
NREL structural biologist Bryon Donohoe commented: “Being able to see the inner workings of this biological catalyst provided us with the blueprints to engineer a faster and more efficient enzyme.”
It was while the team were working on how the PETase enzyme worked out how to break plastics down, they created a mutant PETase enzyme which could be further improved upon to tackle plastics.
“This unanticipated discovery suggests there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics,” said McGeehan
The PETase mutant is 20 percent more efficient than its natural occurring PETase cousin.
This means that future enzyme creations can be engineered to create better mutants to munch through the billions of tonnes of plastic already amassed.
It appears that science can now provide a helping hand to nature in tackling one of the world’s biggest pollution problems.