A couple years back, scientists discovered bacteria at a Japanese recycling plant that were breaking down a common type of plastic known as polyethylene terephthalate, or PET. With the hope of developing a solution to the world’s chronic plastic pollution problem, British and American researchers decided to study the enzyme that the bacteria were using to digest this ubiquitous substance—and now they’ve made a stunning discovery.
The researchers were only trying to model the enzyme, known as PETase, in order to understand how it works. But they ended up accidentally engineering a “mutant” version of the enzyme that’s even better at degrading PET plastic than the natural version found in the Japanese recycling center.
“Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception,” said University of Portsmouth professor John McGeehan, who conducted the research with Gregg Beckham of the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL,) in a statement.
“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.”
The world has a serious plastic crisis right now. There are massive accumulations of trash, largely plastic-based, floating in our oceans—the largest, in the North Pacific, is now bigger than Alaska. Marine life is choking on it. And our water supplies, both through faucets and in bottles, are also largely contaminated with tiny particles of plastic.
So an industrial process that could make the stuff easier to recycle would be most welcome.
“We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these ‘wonder-materials,’ must now use all the technology at their disposal to develop real solutions,” said McGeehan.
The researchers say the PETase mutant enzyme could also be used to degrade polyethylene furandicarboxylate (PEF,) which is a newer polymer that’s being increasingly used to make bottles.
As for when we can expect to see industrial degradation processes developed using this enzyme, in order to make plastics more recyclable, that depends on how well the researchers can improve its performance through engineering.
“This research is just the beginning and there is much more to be done in this area,” said Harry Austin, the postgraduate student who was the lead author on the researchers’ paper.