Biodegradation & Composting

Largs Scientist Makes ‘Global Discovery’ That Could Save Our Oceans – By Accident

A LARGS scientist has helped to create a plastic-eating enzyme which could revolutionise recycling across the world.

Former St Mary’s and Largs Academy pupil John McGeehan created the plastic-digesting protein accidentally while investigating its natural components. The professor and his team however hope that it could usher in a new form of reusing plastic waste. John said: “Serendipity often plays a significant role in fundamental scientific research, and our discovery here is no exception.

“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 technology exists and it’s well within the possibility that in the coming years we will see an industrially viable process to turn polyethylene terephthalate plastic and potentially other plastics back to their original building blocks so that they can be sustainably recycled.”

Tests showed that the lab-made mutant enzyme had an ability to break down one of the most popular forms of plastic used by the food and drinks industry.

Bottles made from this material are used to package 70 per cent of soft drinks, fruit juices and mineral waters sold in shops and supermarkets, according to the British Plastics Federation.

Whilst it can at the moment be recycled, any discarded the plastic can last in the environment for hundreds of years before it degrades.

John, who is the director of the Institute of Biological and Biomedical Sciences at Portsmouth, added: “Few could have predicted that since plastics became popular in the 1960s, so much would now be found floating in oceans or washed up on once pristine beaches all over the world.

“We can all play a significant part in dealing with the problem, but the scientific community who ultimately created these ‘wonder-materials’ must now use all the technology at their disposal to develop real solutions.”

The new research sprang from the discovery of bacteria in a Japanese waste recycling centre that had evolved the ability to feed on plastic.

The bugs used a natural enzyme to digest the bottles and containers.

While probing the molecular structure of PETase, the John and his team inadvertently created a powerful new version of the protein.

The findings are reported in the journal Proceedings of the National Academy of Sciences.

Working with US colleagues, the scientists subjected PETase to intense X-ray beams which are 10 billion times brighter than the sun.

Using the PETase blueprint provided, the scientists re-engineered an active region of the molecule which resulted in the mutant protein with an enhanced ability to attack plastic.

In addition to digesting it, the new enzyme was also capable of degrading polyethylene, a bio-based form of plastic being hailed as a replacement for glass beer bottles.


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