Scientists have created an enzyme which eats plastic quickly

Scientists have accidentally engineered a stronger version of an enzyme which naturally eats a widely used type of plastic.

The researchers at the University of Portsmouth and the US National Renewable Energy Laboratory (NREL) made the discovery while analysing the structure of a naturally existing enzyme which consumes plastic.

The original enzyme was found at a recycling centre in Japan a few years ago and has the ability to break down polyethylene terephthalate, known as PET, which is extensively used to make millions of plastic bottles around the world.

By trying to understand how this enzyme had evolved the researchers managed to solve its crystal structure. In doing so they inadvertently developed a mutant variation that was 20 percent stronger at dissolving PET than its natural equivalent. This new version can reportedly take days to start breaking down the plastic.

“Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception,” said Professor McGeehan at the University of Portsmouth.

“Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics.”

As with all types of plastic, PET is non-biodegradable and exists in the environment for hundreds of years. “It is incredibly resistant to degradation. Some of those images are horrific,” McGeehan told The Guardian, referring to how plastic destroys marine wildlife. “It is one of these wonder materials that has been made a little bit too well.”

This new finding provides the exciting possibility that the enzyme could be used on an industrial scale to recycle plastic bottles back into bottles. This would stop the need to create new plastic to make new ones.

Their research is published in the journal Proceedings of the National Academy of Sciences. Lead author Harry Austin, a postgraduate student at the University added: “This research is just the beginning and there is much more to be done in this area.”

The team is intending to continue work on the enzyme to see if they can make it even stronger.

“It will be interesting to see whether, based on this study, the performance of the enzyme can be improved and made suitable for industrial-scale application in the recycling and the future circular economy of plastic,” said Dr Colin Miles at the Biotechnology and Biological Sciences Research Council, which funded the research.