The need for more sustainable polymer chemistry has spurred progress in biocompatible materials and biocatalysts for polymer processing and recycling. However, current methods lack specificity and result in poor-quality products and side reactions. The CIRCULARIZE project, funded by the ERC, aims to address these challenges by developing chemio-enzymatic methods that transform biocompatible resources into advanced functional materials. The project focuses on enhancing the efficiency of biocatalysts, improving material properties and creating new smart materials with reactive surfaces. CIRCULARIZE strives to establish sustainable, highly selective processes that minimise damage to monomers and polymers, ultimately advancing biocompatible hybrid polymers with temperature-switchable and enzyme-sensitive properties, paving the way for a circular economy for biopolymers.