Preparation and evaluation of antibacterial activity of Ag+ supported modified Japanese cedar biomass

Abstract A novel antibacterial agent was synthesized from Japanese cedar sawdust, a representative woody biomass resource, through chemical modification using potassium permanganate. The oxidation treatment introduced carboxyl groups onto the biomass surface, providing active sites for Ag + adsorption. X-ray photoelectron spectroscopy (XPS) analysis revealed characteristic Ag 3d peaks at 367.8 and 373.8 eV, confirming the successful adsorption of Ag + onto the modified biomass. The saturated adsorption capacities of Ag + were determined to be 48.3 mg g − 1 by the batch method and 73.5 mg g − 1 by the column method. The antibacterial activity of the resulting Ag + -adsorbed material (Cedar-O-Ag) was evaluated against Escherichia coli by observing turbidity, Ag + release, and colony formation. Cedar-O-Ag induced bacterial cell lysis, with complete bactericidal activity observed at 50 mg, corresponding to an Ag + concentration of 0.347 mmol L − 1 . Colony formation assays confirmed that E. coli growth was entirely inhibited at this concentration. Furthermore, reusability tests demonstrated that Cedar-O-Ag maintained bactericidal activity for up to three consecutive cycles. Overall, these results show that woody biomass can serve as an effective, sustainable, and reusable carrier for antibacterial materials.