Utilizing endophytic fungus Alternaria tenuissima for silver nanoparticles biogenic formation and their antibacterial efficacy

Due to the growing issue of antibiotic-resistant microorganisms, it is imperative that new antimicrobial medications be developed. Silver nanoparticles give a satisfactory solution for antibiotic resistance that has proven to be a serious impediment to widespread usage of antibiotics. The production of these nanoparticles by biological processes presents a promising avenue for sustainable nanotechnology. The potential of Alternaria tenuissima, an endophytic fungus, as a bio-mediator in the production of silver nanoparticles (AgNPs) is investigated in this work. The fungal biomass filtrate functioned as a natural reducing and capping agent, enabling the rapid and stable formation of AgNPs under ambient conditions. The formed AgNPs were characterized via UV–Visible spectrophotometer, which revealed the high peak at 435 nm, and with the field-emission scanning microscope (FE-SEM), which confirmed the bio-production of predominantly spherical nanoparticles with a mean average size of 17.22 nm. Antibacterial efficacy of biosynthesized AgNPs was evaluated against specific Gram-positive Staphylococcus aureus and Gram-negative bacteria Escherichia coli and Serratia marcescens using the agar well diffusion method. The result revealed significant antibacterial activity from 20 nm to 15 nm, surpassing those of commonly used antibiotics such as Novobiocin and Tetracycline. The findings underscore the efficacy of A. tenuissima in silver nanoparticle fabrication and reinforce the promise of fungal biogenic AgNPs as eco-friendly antimicrobial agents for biomedical and pharmaceutical applications.