Hodhod, Mohamed SGaafar, Abdel-Rhman ZAlMunqedhi, Bandar MElzein, Abdalla2023-10-262023-10-262023-10https://doi.org/10.1515/chem-2023-0139http://repository.msa.edu.eg/xmlui/handle/123456789/5755https://www.scimagojr.com/journalsearch.php?q=21100384025&tip=sid&clean=0Bio-nanotechnology provided an ecofriendly synth- esis route for various metal nanoparticles by utilizing dif- ferent biological systems, especially microorganisms, which act as an alternative to the physical and chemical methods. Cobalt nanoparticles (CoNPs) were synthesized by Periconia prolifica (Anast.) from intertidal decayed wood samples from the mangrove tree Avicennia marina (Forsk.) of Tarout Island, located in the Arabian Gulf Sea of Saudi Arabia. CoNPs were characterized by X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and atomic force microscope. The extract of the culture of P. prolifica was used as a bio-reductant agent, during which the culturing process proved to have great potential to be applied on an industrial scale, as it was a time-saving, inex- pensive, and adequate amount of biomass being produced at the end of the process. A preliminary antibacterial test against one Gram-positive resistant bacteria (i.e., Methicillin-resistant Staphylococcus aureus) and other Gram-negative resistant bacteria was performed using a disk diffusion assay. The antibacterial results witnessed the key role that metal size plays in causing higher activity and also in causing severe damage to the bacterial cells by inactivating its membrane permeability, leading to bacterial cell death.enmarine fungi, Periconia prolifica, CoNPs, char- acterization, antibacterial activityArticlehttps://doi.org/10.1515/chem-2023-0139