Harnessing enzymes for greener polymerisations: advances in chain and step growth processes

Synthetic organic polymers face increasing scrutiny due to their environmental impact, as most industrial monomers are petrol-based. Key concerns include fossil fuel consumption, greenhouse gas emissions, reliance on non-renewable feedstocks, insufficient recycling and the use of toxic and harmful catalysts. To align with the United Nations Sustainable Development Goals (SDGs) and Anastas and Warner's 12 Principles of Green Chemistry, the polymer industry must embrace a total revolution. Biocatalysis offers a promising route to achieve these goals. This review encourages the polymer community to adopt enzymatic catalysis for functional polymer synthesis, showcasing enzymes as powerful tools with green credentials that should be integrated into the field. To meet field-specific nomenclature we categorise enzymatic polymerisation based on the more general mechanisms, namely step polymerisation (SP), chain polymerisation (CP), and ring-opening polymerisation (ROP), reflecting the recent refinement of ‘step-growth’ and ‘chain-growth’ nomenclature by the IUPAC's Subcommittee on Polymer Terminology. This classification aims to engage readers with interests directed towards polymerisation processes and direct utilisation of the enzymes to specific reagents or classes of monomers. By presenting examples and using familiar mechanistic categorisations in a tutorial-style review, we aim to empower polymer chemistry researchers to embrace enzymatic catalysis as a sustainable and innovative tool. We conclude the review by highlighting recent innovative works, discussing challenges and proposing future opportunities.