A new cocktail of enzymes that speeds up the degradation of plastic offers a step forward in finding a new form of recycling that is faster, more affordable and works on a larger scale than current methods, British and American researchers said.
The “super-enzyme” could be employed to break down plastic bottles much more quickly than current recycling methods and create the raw material to make new ones, the scientists said. And it may make it easier to repurpose the material. “This is a very exciting development for plastics recycling and environmental stewardship,” said Jim Pfaendtner, a professor of chemistry at the University of Washington.
An estimated 359 million tons of plastic is produced annually worldwide, with at least 150 million tons of it sitting in landfills or in the environment. Plastics may take up to 450 years to degrade in the ocean, if they do at all, the National Oceanic and Atmospheric Administration said. Much of it breaks down into microplastics that have been found in marine life, ocean water and in the guts of humans.
As the world confronts climate change and the need to burn far less fossil fuel, oil and gas companies are turning to manufacturing more plastics like PET, one of the most popular plastics in the world. It is found in soda bottles, synthetic clothing and packaging.
The study, published in the journal PNAS from a team of scientists at the University of Portsmouth and the National Renewable Energy Laboratory and other U.S. institutions, focuses on a combination of two enzymes derived from a bacterium discovered in Japan in 2016. The scientists found that this bacterium could break down PET.
In 2018, the team had success breaking down plastic using one of the two enzymes. But when the second enzyme is added, students found, the process works six times as fast. “You get the original building blocks back,” said Prof. John McGeehan, director of the Center for Enzyme Innovation and co-leader of the team. And those building blocks can then be used over again.