Next-generation biopolymers: transforming agri-food residues into advanced materials

The global need to mitigate plastic waste accumulation necessitates rapid, innovative strategies to replace fossil-based, non-biodegradable materials. This research addresses this challenge by evaluating the potential of diverse agro-industrial residues as functional components for next-generation green polymers, effectively bridging the gap between waste management and material science. The study adopts a multifaceted approach to valorize these residues. Initially, chestnut shell residues were characterized and incorporated as fillers into poly(butylene succinate-co-adipate) (PBSA), imparting significant functional advantages such as antioxidant and antibacterial activities to the final material. In collaboration with ENEA and DISTAL (University of Bologna), spent brewer’s yeast was subsequently processed through innovative methods to enhance its utility. This residue was successfully applied as a filler in poly(butylene succinate) (PBS), as a foundational element for sodium alginate-based edible films, as an active coating to modify substrate hydrophilicity, and as a water-soluble adhesive that leverages the residue's intrinsic protein content. Furthermore, the research explored the development of compostable labels using bacterial cellulose produced in partnership with DISTAL (University of Bologna), utilizing a bio-based adhesive to ensure optimal affinity with polymeric films. Finally, in collaboration with Toso Montanari (University of Bologna), the study investigated 2,5-bishydroxymethylfuran (BHMF), a derivative of plant-based 5-(hydroxymethyl)furfural (HMF), as a precursor for novel bio-based polymers via both enzymatic and solvent-based polymerization techniques. These findings demonstrate that agro-industrial waste can be successfully transformed into high-value materials. By supporting a circular economy model, this research not only reduces the environmental footprint of the packaging industry but also introduces superior functional properties. The development of compostable labels and the synthesis of polymers from renewable monomers like BHMF confirm the technical feasibility of replacing fossil-fuel-dependent products with sustainable, high-performance alternatives, ultimately providing a versatile toolkit for advancing sustainable material science.