Plastics and Bioplastics End of Life: A Biocatalytic Perspective.

Plastics have become indispensable to modern society, but their predominantly linear production and end-of-life management are increasingly incompatible with environmental and resource constraints. Biotechnology offers new opportunities to reshape this system, not only by enabling the biological recycling and upcycling of conventional plastics, but also by supporting the production and end-of-life management of more sustainable bioplastics. Recent progress in plastic-degrading enzymes, particularly for PET, has demonstrated the potential of biocatalysis, yet it has also made clear that enzyme performance alone will not determine whether these technologies succeed at scale. Real waste streams, sorting and pretreatment requirements, process economics and integration with existing recycling infrastructure remain decisive constraints. The same systems perspective is needed for bioplastics: Bio-based origin or biodegradability does not automatically translate into circularity, and their environmental value ultimately depends on how materials are designed, used, collected and treated after use. In this Opinion, we argue that biocatalysis should therefore be developed as part of realistic circular plastic systems rather than as a universal solution to plastic waste. Combining advances in enzymatic and microbial technologies with Safe-and-Sustainable-by-Design principles and credible end-of-life pathways could enable plastics and bioplastics to move towards genuinely circular material cycles while reducing dependence on fossil carbon and limiting plastic pollution.