Scientists Accidentally Create Super Enzyme That Can Devour Plastic Pollution

David Jones

David Jones

The scientists in just such a scenario comprise an worldwide team that was working off of a 2016 discovery of the first bacterium that had naturally evolved to eat plastic.

The findings were published Monday in the Proceedings of the National Academy of Sciences journal.

McGeehan and colleagues were examining the structure of the natural, PET-degrading enzyme when they found they could increase the degradation rate by manipulating the chemical structure of the enzyme.

This discovery follows the discovery in 2016 of an enzyme that naturally evolved into a Japanese dump.

The impact of such an innovative solution to plastic waste would be global.

Professor John McGeehan, director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth, said: "What we are hoping to do is use this enzyme to turn this plastic back into its original components, so we can literally recycle it back to plastic..." It also has the potential to recycle clear plastic bottles back into clear plastic, which could hugely reduce the need to produce new bottles.

NREL estimates that about eight million metric tons of plastic waste, including PET bottles, enter the oceans each year, creating huge man-made islands of garbage. PET plastics can persist for hundreds of years in the environment and now pollute large areas of land and sea worldwide.

"We originally set out to determine how this enzyme evolved from breaking down cutin-the waxy substance on the surface of plants-with cutinase, to degrading synthetic PET with PETase", said Beckham. They and Gregg Beckham are among the worldwide team of researchers who are working to further improve the enzyme to allow it to be used industrially to break down plastics in a fraction of the time.

When the team tweaked the structure of the enzyme by adding some amino acids, tests showed that it made the molecule even better at breaking down PET plastic. The team used the Diamond Light Source, near Oxford, UK, an intense beam of X-rays that is 10 billion times brighter than the sun and can reveal individual atoms. The structure of PET is too crystalline to be easily broken down and while PET can be recycled, most of it is not. "It gives us scope to use all the technology used in other enzyme development for years and years and make a super-fast enzyme".

"Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception", John McGeehan, a structural biologist from the University of Portsmouth in the United Kingdom, said. The improvement was modest, but the scientists believe bigger improvements are possible by modifying the protein portion of the enzyme. But bacteria are far easier to harness for industrial uses.

The sheer magnitude of the plastic pollution problem on planet Earth can no longer be ignored, as plastics can be spotted covering beachings, floating in oceans, and even lining the stomachs of whales. Because it's virtually invincible against microbes, however, the plastic never degrades, making it a pollutant scourge on the environment.

"Enzymes are non-toxic, biodegradable and can be produced in large amounts by microorganisms", he said. "[But] this is certainly a step in a positive direction". And obviously, reducing the production and use of single-use plastics in the first place can't be emphasized enough.

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