Horseradish Peroxidase-Mediated Synthesis of an Antibacterial Gallic Acid-g-Chitosan Derivative and Eco-friendly Dyeing of Silk Fabric

In this study, gallic acid-g-chitosan colored complexes were produced using the HRP-catalyzed method and successfully used to dye silk fabrics. The reaction mechanism was studied using FT-IR, H-1-NMR, and ESI-MS technologies; the dyed silk fabrics were characterized through K/S, color fastness, and antibacterial tests. In addition, an in situ staining process based on enzyme catalysis was explored to simplify the pretreatment process of chitosan. Chitosan and gallic acid were polymerized through O-Ph, Ph-Ph and amino-phenyl bonds to form a dark-yellow polymer that was successfully used to dye silk fabrics. In addition, significant color differences were observed between fabrics dyed without chitosan and dyed in the presence of chitosan. As a result, gallic acid-g-chitosan dyes polymerized via HRP catalysis improved the antimicrobial properties of the colored fabrics without significantly affecting the color fastness of the silk fabrics.