Antibacterial and Photocatalytic Performance of EPS-Stabilized Silver Nanoparticles Immobilized on Activated Natural Zeolite

Biopolymers have emerged as effective stabilizing and capping agents in the green synthesis of metal nanoparticles due to their biocompatible, hydrophilic, and eco-friendly nature. Among these, bacterial polysaccharides, particularly exopolysaccharides (EPSs), offer distinct advantages over plant, algal, and fungal derived polymers, owing to their unique chemical structure rich in negatively charged functional groups that facilitate interactions with metal ions and enhance nanoparticles’ stability. Despite their properties, the practical application of AgNPs is often limited by aggregation, colloidal instability, and uncontrolled ion release. To address these challenges, in the present study, EPS-stabilized silver nanoparticles (AgNPs) were synthesized using a green approach. The synthesized biogenic AgNPs were immobilized with natural zeolite, a porous inorganic material, to improve stability and regulate functionality. The resulting catalytic material was partially characterized using structurally using spectrophotometry (UV-Vis), scanning electron microscope - energy dispersive X-ray analysis (SEM-EDAX), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR). Furthermore, the synthesized green catalyst was evaluated for its photocatalytic degradation against synthetic dyes (methylene blue). In addition, its antibacterial potential was also assessed through determination of inhibitory concentration (IC90) and minimum bactericidal concentration (MBC99), highlighting its potential as a multifunctional biomaterial for environmental and biomedical applications.