POLYSACCHARIDE-REDUCED AND CAPPED GOLD NANOPARTICLES FOR ANTIMICROBIAL AND PHOTOCATALYTIC APPLICATIONS

Abstract

This research investigates the green synthesis of gold nanoparticles (Au NPs) using a biodegradable and natural reducing agent, arabinoxylan mucilage from Plantago major seeds. UV-Vis spectroscopy revealed a characteristic surface plasmon resonance peak at 550 nm, with an energy band gap of 3.45 eV, confirming Au NP formation. FTIR analysis revealed peaks corresponding to alcohol, carbonyl, and other functional groups, along with a distinct metal-oxygen bond signal, demonstrating the participation of the groups in NP stabilization. SEM revealed globular-shaped particles (78 nm), while EDX analysis confirmed the elemental composition. XRD patterns verified the crystalline NPs with a face-centered cubic structure. The Au NPs exhibited effective microbicidal potential against Escherichia coli (ZOI 25 ± 0.66 mm), Bacillus cereus (ZOI 18 ± 0.33 mm), and Enterobacter aerogenes (ZOI 11 ± 0.98 mm). The significant minimum inhibitory and bactericidal concentrations (MICs and MBCs) were investigated for bacterial strains, confirming the antimicrobial potential of Au NPs. Furthermore, the Au NPs demonstrated remarkable photocatalytic performance with degradation efficiencies of 89% for methylene blue (MB) and 81.19% for methyl orange (MO) under pseudo-first-order kinetics, highlighting their potential for wastewater treatment.