One of the worlds biggest environmental problems is plastics recycling and waste.

One of the world's biggest environmental problems is plastics recycling and waste.

Scientists have engineered an enzyme that can break down polyester more efficiently in a breakthrough that could provide a solution to one of the world's biggest environmental problems: plastics recycling and waste.

The research, led by scientists at the University of Portsmouth and the US Department of Energy's National Renewable Energy Laboratory (NREL), inadvertently engineered the enzyme, which can digest some of the most commonly polluting plastics.

One of those is polyethylene terephthalate (PET), which is used in polyester fibres for clothing. It can be recycled until it is useless and ends up as waste.

"Few could have predicted that since plastics became popular in the 1960s huge plastic waste patches would be found floating in oceans, or washed up on once pristine beaches all over the world," says Professor McGeehan, director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth.

"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."

Scientists believe the discovery could result in an enzyme that would degrade PET, and potentially other substrates like PEF, PLA, and PBS, back into their original chemical chains so they can be sustainably recycled.

The breakthrough was made when scientists were examining the structure of a natural enzyme, which is thought to have evolved in a waste recycling centre in Japan, allowing a bacterium to degrade plastic as a food source.

The goal was to determine its structure, but they ended up going a step further and accidentally engineered an enzyme that was even more efficient at breaking down PET plastics.

"Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception," Professor McGeehan said. "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 scientists used Plymouth University's Diamond Light Source – a synchrotron that uses intense beams of X-rays 10 billion times brighter than the sun to act as a microscope powerful enough to see individual atoms – to help with the research.

Professor Andrew Harrison, chief executive of the Diamond Light Source at Portsmouth University, added: "The detail the team were able to draw out from the results achieved on the I23 beamline at Diamond will be invaluable in looking to tailor the enzyme for use in large-scale industrial recycling processes. The impact of such an innovative solution to plastic waste would be global. It is fantastic that UK scientists and facilities are helping to lead the way."

Similar enzymatic research is underway at French bioplastics firm Carbios, as reported on just-style last month:

New process turns polyester waste into virgin PET