Development of a Multi-Enzymatic Approach for the Modification of Biopolymers with Ferulic Acid

A series of polymers, including chitosan (CS), carboxymethylcellulose (CMC) and a chitosan–gelatin (CS–GEL) hybrid polymer, were functionalized with ferulic acid (FA) derived from the enzymatic treatment of arabinoxylan through the synergistic action of two enzymes, namely, xylanase and feruloyl esterase. Subsequently, the ferulic acid served as the substrate for laccase from Agaricus bisporus (AbL) in order to enzymatically functionalize the above-mentioned polymers. The successful grafting of the oxidized ferulic acid products onto the different polymers was confirmed through ultraviolet–visible (UV–Vis) spectroscopy, attenuated total reflectance (ATR) spectroscopy, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy. Additionally, an enhancement of the antioxidant properties of the functionalized polymers was observed according to the DDPH and ABTS protocols. Finally, the modified polymers exhibited strong antimicrobial activity against bacterial populations of Escherichia coli BL21DE3 strain, suggesting their potential application in pharmaceutical, cosmeceutical and food industries.