Green Synthesis, Structural Characterization, and Antimicrobial Activity of ZnO Nanoparticles Using Cladosporium cladosporioides

Introduction: This study aimed to synthesize zinc oxide nanoparticles (ZnONPs) using the marine endophytic fungus Cladosporium cladosporioides through an eco-friendly green synthesis method and to evaluate their antimicrobial activities. Methods: C. cladosporioides was cultured in Potato Dextrose Broth (PDB), and biomass was optimized for various ZnCl2 concentrations, pH, temperature, and incubation times. The synthesized ZnONPs were characterized using SEM, EDAX, FTIR, UV-Vis, and zeta potential analyses, and their antimicrobial activity was tested using the disk diffusion method. objective: In this study, the pellet parts of a marine endophytic fungus, Cladosporium cladosporioides, were used for the synthesis of Zn nanoparticles (ZnONP). To achieve high yield, the production conditions of the microorganisms and then the reaction environment were optimized. The biomass, ZnCl2 concentration, incubation time, temperature, pH, and mixing conditions were determined, and the characterization of the synthesized ZnONPs was obtained through SEM, EDAX, FTIR, UV-Vis spectroscopy, and Zeta potential analyses. Results: The optimum conditions were determined as 1 g biomass, 10 mM ZnCl2, pH 7, 45°C, and 100 rpm. Spherical ZnONPs with a size of approximately 60-70 nm and a zeta potential of -20.7 mV were obtained. Inhibition was observed against all tested microorganisms except Enterococcus faecalis and Candida albicans. Discussion: The findings support the antimicrobial potential and stability of ZnONPs. The green synthesis method offers a safer alternative to chemical synthesis in terms of environmental and health impacts. Conclusion: ZnONPs produced using C. cladosporioides have potential as broad-spectrum antimicrobial agents.