New enzyme cocktail digests plastic waste

Image made by CMCNEWG from a waste plastic image by Meaduva.

New enzyme cocktail digests plastic waste ‘six times faster’

A discovery by a University of Portsmouth team is seen as a ‘leap towards beating plastic waste’. The scientists who previously re-engineered the plastic-eating enzyme PETase, have created an enzyme ‘cocktail’ that can digest plastic up to six times faster. 

A second enzyme found in the same waste dwelling bacterium that lives on a diet of plastic bottles, has been combined with PETase to speed up the breakdown of plastic.  PETase breaks down polyethylene terephthalate (PET), the most common thermoplastic, used to make single-use drinks bottles, clothing and carpets, back into its building blocks, creating an opportunity to recycle plastic infinitely, reducing both plastic pollution and the greenhouse gases driving climate change.  PET takes hundreds of years to break down in the environment but PETase can shorten this time to days.

The same team have combined PETase and its ‘partner’, an enzyme called MHETase, to generate much bigger improvements; mixing PETase with MHETase doubled the speed of PET breakdown and engineering a connection between the two enzymes to create a ‘super-enzyme’, increased this activity by a further three times, a total of six times faster!.

The original PETase enzyme discovery raised the first hope that a solution to the problem of global plastic pollution might be within grasp, although PETase alone is not yet fast enough to make the process commercially viable to handle the tons of discarded PET bottles littering the planet. 

Combining it with a second enzyme and finding together they work even faster, means another leap forward has been taken towards finding a solution to plastic waste.  PETase and the new combined MHETase-PETase both work by digesting PET plastic and returning it to its original building blocks, which allows for plastics to be made and reused endlessly, reducing our reliance on fossil resources such as oil and gas.

The appliance of science wins again!