Enzyme used in laundry detergent can recycle single-use plastics in 24 hours

Scientists at King’s College London have developed an innovative solution to recycle single-use bioplastics commonly used in disposable items such as coffee cups and food containers.

The new chemical recycling method, published in Cellular Reports Physical Sciences, uses enzymes typically found in organic laundry detergents to “depolymerize” – or break down – landfill-bound bioplastics. By rapidly converting elements into soluble fragments in just 24 hours, the process allows for complete degradation of the bioplastic polylactic acid (PLA). This approach is 84 times faster than the 12-week industrial composting process used to recycle bioplastic materials.

This discovery offers a widespread recycling solution for single-use PLA plastics, as the team of chemists at King’s discovered that over an additional 24 hours at a temperature of 90°C, bioplastics break down into their basic chemical elements . Once converted into monomers (single molecules), the materials can be transformed into equally high quality plastic for multiple reuse.

The problem of “green” plastics

Current rates of plastic production exceed our capacity to eliminate it sustainably. According to Environmental Action, it is estimated that in 2023 alone, more than 68 million tonnes of plastic worldwide ended up in natural environments due to the imbalance between the huge volumes of plastic produced and our current capacity to manage and recycle plastic at the end of its production. life. A recent OECD report predicts that the amount of plastic waste produced globally is on track to almost triple by 2060, with around half ending up in landfills and less than a fifth being recycled.

While bioplastics – derived from organic sources such as corn starch, cassava or sugar cane – are seen as a more sustainable choice by consumers, current methods of producing bioplastics are expensive and compete with agriculture food for land use. Meanwhile, mechanical recycling methods are inefficient and generate CO₂ and are unable to produce high quality reusable materials. These “green” plastics mostly end up in landfills after just one use, pushing many retailers back to using petroleum and fossil-based materials.

The speed at which bioplastics break down using this new method could revolutionize plastic production, providing an efficient, scalable and sustainable model for recycling single-use bioplastics. A significant breakthrough in the recyclability of single-use bioplastics, the research paves the way for a circular and sustainable economy that eradicates the production of fossil-based plastics and tackles the enormous volume of plastic waste that ends up in landfills and in natural environments. .

Dr Alex Brogan, senior lecturer in chemistry at King’s College London, said: “The inspiration for this project came from a problem with bioplastics used in medical and surgical products breaking down in the body. We turned this problem around and applied it to the issue of recycling the single-use bioplastics we use in our daily lives using a common enzyme found in organic laundry detergents. Being able to harness biology to provide sustainable solutions through chemistry allows us to start viewing waste as a resource so we can move away from oil and other non-renewable sources to create the materials we need for modern life. »

Scientists are now expanding their research to improve the recycling of other commonly used and mass-produced plastics, such as those used in single-use water bottles, plastic film and foil packaging, and clothing.

Susana Meza Huaman, Ph.D. researcher on the project at King’s College London, said: “Our research marks the first step in developing new waste management technologies for the recycling of bioplastics that are of equal quality to that of the virgin product. Until now, this has been a major challenge in plastics recycling, because even though bioplastics are made of biological materials, not all of them are compostable and most current recycling methods are inefficient. Our chemical approach significantly accelerates the degradation of bioplastics, allowing them to be recycled and reused.