Innovative enzyme technology leads the fight against plastic waste
Unrecyclable plastic waste poses a growing environmental and economic challenge. The EU-28 generates over 27 million tonnes of plastic waste annually, with only about 31 % being recyclable. To address the massive environmental burden of non-recycled plastics, the EU-funded ENZYCLE project focused on developing innovative enzyme-based solutions to degrade currently non-recyclable plastics, including microplastics in wastewater.
Targeting non-recycled plastic fractions
The project’s primary aim was to valorise non-recycled plastic fractions through enzymatic degradation processes. This includes targeting polyethylene terephthalate (PET) and polyolefins – such as polyethylene (PE) and polypropylene (PP) in the form of post-consumer PET trays, clamshell containers and multilayer packaging – products that conventional recycling processes struggle to handle. ENZYCLE utilised a range of enzymes, including leaf-branch compost cutinase (LCC) and metagenome-derived polyester hydrolase (PHL7). Both of these demonstrated high hydrolytic activity on PET. “PHL7 can degrade 90 % of PET in just 16 hours, significantly outperforming previous enzymes like LCC,” says the team at ITENE research centre, Spain, ENZYCLE project coordinator.
Innovative recycling methods
ENZYCLE introduced a microplastic degradation system (MDS) that combined enzymatic and microbiological processes to break down microplastics, such as PET, PE and polyamide, achieving a 30 % weight loss in these microplastics. This innovative process provides an alternative to traditional thermal recycling methods, which are often energy-intensive and degrade the quality of plastic material. Unlike thermal methods, enzymatic recycling takes place at lower temperatures and in an aqueous environment, which is far more sustainable. “Enzymes break down PET into reusable components, terephthalic acid, and ethylene glycol, facilitating high-quality recycling. These advantages make enzymatic recycling a more sustainable and effective alternative,” the ITENE team adds. This approach facilitates the recovery of valuable resources that can be repurposed in high-quality applications and enhances the efficiency of the recycling process, closing the loop in plastic manufacturing.
Real-world results and challenges
Despite the progress, ENZYCLE faced significant challenges. One of the main obstacles was scaling the enzyme production process to an industrial level while keeping costs in check. By adopting a two-step continuous culture process and enhancing enzyme stability through protein engineering, the project successfully made large-scale enzyme production industrially viable. However, the project encountered difficulties optimising biological processes for real microplastics from wastewater treatment plants. As the ITENE team notes, “Challenges include optimising biological processes for real microplastics from wastewater treatment plants and scaling the laboratory-developed process to industrial levels while considering enzyme costs."
Future opportunities in the circular economy
The innovations introduced by ENZYCLE extend beyond traditional plastic recycling. By fostering collaboration between the biotechnology and waste management sectors, the project has opened the door to new value chains. These partnerships enable recycling companies to explore advanced waste recovery methods while supplying the biotechnology industry with fresh raw materials, all in alignment with circular economy principles. This synergy can potentially drive advancements in bioengineered materials, green manufacturing technologies and sustainable packaging solutions.
Impact on sustainability and society
ENZYCLE’s enzymatic solutions promise to significantly reduce plastic waste's environmental footprint, especially with non-recycled fractions. By minimising plastic pollution and improving waste management practices, the project helps protect ecosystems and biodiversity while contributing to human health. In addition, ENZYCLE’s approach aligns with the broader goals of the circular economy, which aims to reduce reliance on raw materials and fossil fuels and promotes reskilling and job creation in the biotechnology and waste management sectors.
Keywords
ENZYCLE, microplastics, circular economy, enzymatic degradation, plastic recycling, sustainable waste management
