Biosynthesis of iron nanoparticles by Westerdykella dispersa and their application in synthetic dye decolorization

This study reports, for the first time, the green synthesis of iron nanoparticles (FeNPs) using Westerdykella dispersa (AmlDm3), a fungal species not previously associated with FeNP production. The isolate, recovered from wastewater-contaminated sites in Dammam, Saudi Arabia, was identified through morphological examination and ITS-based phylogenetic analysis. UV–Vis spectroscopy confirmed nanoparticle formation with a characteristic absorption peak at 240 nm. SEM analysis revealed predominantly spherical nanoparticles, while zeta potential measurements indicated moderate colloidal stability (–20.2 mV). FTIR spectra demonstrated the presence of Fe–O, COO⁻, C–O, and amide functional groups, suggesting stabilization by fungal biomolecules. EDX analysis further verified the elemental composition of iron-based nanoparticles. The synthesized FeNPs exhibited rapid catalytic performance, achieving 95.09 ± 0.08% decolorization of malachite green within 5 min at 0.2 mg/mL, with a maximum removal efficiency of 96.72 ± 0.03% after 24 h. Methyl violet and methylene blue showed decolorization efficiencies up to ~85%, whereas safranin reached ~69%. Effective dye removal was also maintained under mixed-dye conditions and at low nanoparticle dosages. No antimicrobial activity was observed. Overall, W. dispersa-mediated FeNPs represent a rapid, efficient, and sustainable nanobiotechnological platform for environmentally friendly wastewater remediation.