Source: Sky News
British scientists have engineered an enzyme which can digest polyethylene terephthalate (PET), the plastic used in single-use plastic bottles and other common packaging.
Tests showed that the lab-made mutant enzyme had a supercharged ability to break down PET, one of the most popular forms of plastic used by the food and drinks industry.
Bottles made from PET are used to package 70% of soft drinks, fruit juices and mineral waters, according to the British Plastics Federation.
PET persists for hundreds of years in the environment before it degrades and the discovery may mean that significantly more plastic waste could be recycled.
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 called PETase to digest PET bottles and containers.
While analysing the molecular structure of PETase, scientists at the University of Portsmouth accidentally created a powerful new version of the protein.
Working with the US Department of Energy’s National Renewable Energy Laboratory (NREL), the scientists subjected PETase to intense X-ray beams at the Diamond Light Source synchrotron facility in Harwell, Oxfordshire.
X-rays 10 billion times brighter than the sun are generated at the facility by accelerating electrons around a circular tunnel.
The X-rays can be used to reveal the fine structure of materials and biomolecules, down to the level of individual atoms.
Using the PETase blueprint provided by the Diamond Light Sources, the scientists re-engineered an active region of the molecule.
The result was a mutant protein with an enhanced ability to attack plastic.
It could also attack another form of plastic, polyethylene furandicarboxylate (PEF), a bio-based substitute for PET plastics that is being hailed as a replacement for glass beer bottles.
“Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception,” said Professor John McGeehan, director of the Institute of Biological and Biomedical Sciences at Portsmouth University.
“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.”