The ENZYCLE project will develop processes to recycle plastics that are currently not recycled, such as multilayer packaging materials and microplastics from wastewater based on selective enzymatic back-to-monomer degradation.
The majority of plastics produced worldwide are not re-used, but instead end up either in landfills or the environment (land, surface water and oceans). As well as causing huge environmental problems, this leads to a loss of valuable resources. While the mechanical recycling of plastic waste offers a solution, it often leads to a loss of material quality and is poorly suited for the recycling of materials consisting of more than a single polymer. In the ENZYCLE project, we will investigate solutions to these problems based on the application of enzymes to recycle plastics that are currently not recycled. In particular, ENZYCLE aims to develop enzymatic approaches for the recycling of multilayer packaging materials and microplastic particles from wastewater.
Currently, plastic packaging materials are often composed of multiple layers of different polymers in order to meet the functional requirements (such as gas or moisture-barrier properties) of their application. These multilayer packaging materials are hard to recycle in conventional mechanical recycling systems. In ENZYCLE, we will develop methodologies for the recycling of multilayer packaging materials composed of a polyester (PET) and a polyolefin (PE or PP). Specific hydrolase enzymes are known to degrade PET into its monomeric building blocks ethylene glycol and terephthalic acid. In this project, we will exploit the selectivity of PET-degrading enzymes to develop a process in which enzymes degrade the PET into monomers that can be recovered and used to produce new polymers, while leaving the polyolefin intact for processing via existing recycling technologies.
Microplastics in wastewater
Wastewater is often polluted with microplastic particles, composed of polymers such as polyolefins. ENZYCLE will conduct a search in nature, by screening microorganisms and metagenomic data, to identify enzymes capable of degrading such polyolefins. The enzymes responsible for polyolefin degradation will be identified and employed in a process to remove microplastics from wastewater. The degradation products will be isolated and re-used in the production of new polymers.