Scientists who re-engineered the enzyme PET-ase have created an enzyme ‘cocktail’ which can digest plastic up to SIX times faster.
Scientists have previously discovered that the enzyme PETase can be genetically engineered to break down the very substance that we humans are using to ruin our planet – Plastic. More recently however, further developments have been made. A second enzyme has been found in the same rubbish-dwelling bacteria that typically lives on a diet of plastic bottles. This enzyme has been harvested and combined with PETase to achieve plastic breakdown speeds up to six times as quickly as before.
PETase breaks down a substance called polyethylene terephthalate. This is more commonly known as PET, and is a clear, strong & lightweight plastic commonly used for packaging foodstuff and beverages. PETase breaks PET used back into its building blocks, creating an exciting opportunity to recycle plastic infinitely and reduce our vast plastic pollution levels. Typically, PET takes hundreds of years to break down in the natural world, but this remarkable enzyme can reduce this time to a matter of DAYS.
The initial discovery was a potential revolution in regards to recycling plastic, creating a possible low-energy solution to tackle plastic waste. A team of scientists working across the Atlantic engineered the natural PETase enzyme in the laboratory to work 20% more efficiently at breaking down the substance. Now, the same team have combined PETase and its partner in crime – a second enzyme called MHETase – to generate much bigger improvements. The simple mix of PETase and MHETase doubled the speed of PET breakdown, and creating a connection between these two brilliant enzymes has created a ‘SUPER-ENZYME’. This increased PET breakdown speeds a further three times.
The team of scientists was co-led by Professor John McGeehan, Director of the Centre for Enzyme Innovation (CEI) at the University of Portsmouth, and Dr Gregg Beckham, Senior Research Fellow at the National Renewable Energy Laboratory (NREL) in the US. They were originally responsible for engineering PETase.
Gregg and I were chatting about how PETase attacks the surface of plastics whilst MHETase works at chopping things up further. It seemed sensible to see if we could combine the two of them, mimicking what happens in nature. Our first experiments showed they combined well together, so we tried to join them like two Pac-Men connected to each other. A huge amount of work was put in on both sides of the Atlantic, but the effort was worth it in the end. We were ecstatic to see our new Enzyme is up to three times quicker than the naturally evolved enzymes working seperately, which opens new directions for further improvements!
Professor John McGeeham, Director of the Centre for Enzyme Innovation at the University of Portsmouth
The original discovery of PETase heralded the first hope that plastic pollution could be a thing of the past, however if it was soon evident that this on its own could not fix the problem. PETase was not quick enough to make the recycling process commercially viable in handling the magnitude of discarded PET bottles littering our planet. Combining it with a second enzyme has given a new hope that we could find a solution to the ever-growing problem of plastic waste.
The Centre for Enzyme Innovation takes enzymes from the natural world and, using synthetic biology, adapts them to create new enzymes to be used in industry. Their research combines structural, computational, biochemical and bioinformatic approaches to reveal insights into enzymes’ molecular structure and exactly how they work. In this case, the research involved a huge team of scientists at varying different stages of their careers, and it turned out to be a huge success.
Lets hope that this work continues, and plastic pollution may, finally, be a thing of the past.
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