Proteins in the design of sustainable plastics alternatives

Abstract Proteins have great potential as renewable materials, and the valorization of protein-rich byproducts in food production and biorefineries can additionally increase the environmental and economical sustainability of these sectors. Proteins are polyamides that are characterized by their extensive intra- and intermolecular interactions. They are stiff and brittle, and have high softening temperatures in the absence of solvents or plasticizers. In this prospective, strategies that convert proteins into mechanically robust and processable materials are summarized. Structure–property relationships are discussed alongside protein modification and material design strategies, and the challenges and outlook for protein-based materials are presented. Graphical abstract