Antimicrobial potential of silver nanoparticles synthesized from mushroom extracts against drug-resistant pathogens

Green synthesis of silver nanoparticles (AgNPs) has emerged as a sustainable alternative to conventional chemical methods due to the presence of natural bioactive compounds in biological systems. Although Ascomycetous macrofungi are rich sources of antibacterial and antioxidant metabolites, their potential in nanoparticle synthesis remains largely unexplored. In the present study, silver nanoparticles were synthesized for the first time using extracts of the Ascomycetous mushrooms Geopora sumneriana and Verpa bohemica as eco-friendly reducing and capping agents. The biosynthesized AgNPs were characterized using UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. UV-visible analysis confirmed nanoparticle formation through a characteristic surface plasmon resonance band at ∼420-450 nm, while FESEM revealed predominantly spherical to hexagonal nanoparticles. XRD analysis confirmed the crystalline nature of AgNPs with a face-centered cubic structure, and FTIR results indicated the involvement of fungal biomolecules such as proteins, phenolics, and polysaccharides in nanoparticle reduction and stabilization. The biosynthesized AgNPs were subsequently evaluated for their antimycotic and antibacterial efficacy, including minimum inhibitory concentration (MIC) determination, against a range of phytopathogenic fungi and clinically relevant bacterial strains. The AgNPs exhibited strong antifungal and antibacterial activities against Aspergillus niger, Penicillium chrysogenum, Pythium ultimum, Escherichia coli, Salmonella gallinarum, and Staphylococcus aureus. The MIC values of AgNPs synthesized using Verpa bohemica ranged from 0.9 to 1.0 mg/mL for fungal strains and 0.7-0.8 mg/mL for bacterial strains. Similarly, AgNPs derived from Geopora sumneriana showed MIC values ranging from 0.6 to 1.1 mg/mL for fungi and 0.4-0.8 mg/mL for bacteria. The pronounced growth inhibition of diverse pathogenic microorganisms underscores the strong antimicrobial potential of these mycosynthesized AgNPs. Overall, the study highlights Geopora sumneriana and Verpa bohemica as efficient biogenic nanofactories and demonstrates the potential of mycosynthesized AgNPs as eco-friendly nanofungicides and nanobactericides for controlling multidrug-resistant pathogens in agriculture, aquaculture, and horticulture.