3.6 Bioactive Cellulose Foams: Linking surface modification and enzyme-catalyzed phenolic acid functionalization to foam structure and stability

To shift from fossil derived foams, it is important to consider cellulose based foams but with value-added properties like bioactivity, to improve its cost effectiveness. In this work, we describe two methods for obtaining biobased foams with strong antioxidant and antibacterial properties. As a first approach, a two-step modification system using polyelectrolyte PolyDADMAC Polydiallyldimethylammonium chloride (PolyDADMAC) and laccase-catalyzed ferulic acid was used to make functionalized cellulose fibers. As a different approach, cellulose fibers were modified using a two-step strategy combining a bioinspired dopamine-based coating and laccase-catalyzed ferulic acid grafting to impart bioactive functionality. The functionalized fibers were converted into low-density and highly porous cellulose-based foams with bioactive and moisture-resistant properties showing high potential for food packaging applications. As such the modified fibers were able to make cellulose-based foams with high antioxidant and antibacterial activity along with certain moisture resistance. These findings highlight the power of combining green chemistry, enzymatic catalysis, and material design to unlock new functionalities in renewable resources, paving the way toward smarter, safer, and more sustainable packaging systems.