Mycosynthesis of zinc sulfide/zinc oxide nanocomposite using Fusarium oxysporum for catalytic degradation of methylene blue dye, antimicrobial, and anticancer activities

In the present study, extracellular cell-free filtrate (CFF) of fungal Fusarium oxysporum f. sp. cucumerinum (FOC) species, was utilized to biosynthesize zinc oxide /zinc sulfide (ZnO/ZnS) nanocomposite. This was achieved by mixing the metal salt with the fungal CFF for 96 h at a temperature of 27 ± 1.0 °C and a pH of 6.5. Several analytical techniques, such as XRD, TEM, UV-Vis, FTIR, DLS, and zeta potential studies, have confirmed the synthesis of NPs. Fungal CFF enzymes and metabolites stabilized produced NPs, according to FTIR. The nanocomposite particle diameter (15-80 nm) was estimated using HR-TEM imaging. The DLS and XRD measurements verified those findings. The zone of inhibition diameter for MRSA was 35 ± 0.21 mm, while B. subtilis measured 33 ± 0.32 mm against the nanocomposite. For E. coli and S. typhi bacterial isolates, it was 25 ± 0.19 and 32 ± 0.36 mm, respectively. The determined MIC value for E. coli was 5,000 µg/mL and MRSA was 500 µg/mL. The ZnO/ZnS nanocomposite has a dose-dependent cytotoxic effect on breast cancer cells, with an IC₅₀ of 197 ± 0.895 µg/mL. The Methylene blue dye was removed by 87.51% using the nanocomposite. Thus, green biosynthesized ZnO/ZnS nanocomposites are recommended for pharmaceutical, industrial, and biological applications.