Green synthesis of TiO₂ nanoparticles using Ganoderma lucidum and Pleurotus ostreatus: Antimicrobial and antioxidant evaluation

Compared to conventional chemical synthesis, the green synthesis of nanoparticles offers a more environmentally friendly approach, helping to reduce pollution and better protect the ecosystem. In this study, TiO₂ nanoparticles were synthesized using aqueous extracts of the well-known mushrooms, Ganoderma lucidum and Pleurotus ostreatus . Structural and morphological characterization was carried out using UV–Visible, XRD, FTIR, SEM, and EDX. UV–Visible analysis indicated strong absorption in the UV region, while FTIR spectra showed a characteristic peak at 654 cm⁻¹ , corresponding to Ti–O and Ti–O–Ti vibrations, confirming nanoparticle synthesis. XRD analysis showed that G. lucidum -derived TiO₂ nanoparticles possessed a smaller average crystallite size, whereas SEM analysis revealed that P. ostreatus -derived TiO₂ nanoparticles exhibited a smaller particle size and lower agglomeration, indicating that crystallite size and particle size followed different trends due to nanoparticle aggregation. SEM images showed predominantly spherical morphology, with reduced agglomeration and finer particle distribution observed in P. ostreatus -mediated NPs. EDX confirmed the presence of titanium and oxygen along with bio-organic residues. In antioxidant assays, P. ostreatus -derived TiO₂ NPs exhibited slightly higher activity with 84.22% inhibition; and IC₅₀ is 14.41 µg/mL compared to G. lucidum -derived NPs with an 81.59% inhibition; and IC₅₀ is 14.49 µg/mL. Antibacterial activity showed that P. ostreatus -derived TiO₂ NPs produced a zone of inhibition of 8.44 mm against C. burnetii , while G. lucidum -derived NPs showed inhibitory effects against Helicobacter species with a zone of 2.79 mm. These findings highlight fungal-mediated synthesis as a sustainable and effective approach for producing bioactive TiO₂ nanoparticles.