Biogenic Synthesis, Characterization, Optimization and Antibacterial Activities of Silver Nanoparticles (AgNPs) from Aspergillus fumigatus Eu.co against Bacterial Pathogens

The biogenic synthesis of silver nanoparticles (AgNPs) by using endophytic fungi is a potential biological nanomanufacturing technique that is cost-effective and environmentally friendly and represents a significant advancement for research in the field of nanotechnology. In this study, AgNO3 was reduced to form silver nanoparticles (AgNPs) by using the mycelial filtrate of Aspergillus fumigatus Eu.co.The characteristics of the AgNPs were evaluated through UV–Visible Spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Elemental Diffraction X-Ray Spectroscopy (EDX) measurements. Furthermore, the applicability of AgNPs as antibacterial agents was detected against a numerous of pathogenic bacteria namely, Salmonella typhi (ATCC7251), Escherichia coli (ATCC 25922), Enterobacter cloacae (ATCC13047), and Proteus mirabilis (ATCC 29906) via a well diffusion assay. The biosynthesis of the biogenic AgNPs was shown by the color shift from yellow to dark brown. The highest UV absorption peak was detected at 420 nm. FTIR analysis of the AgNPs revealed the presence of alcohols, alkanes, unsaturated ketones, and aromatic, nitro and amide groups that are associated with bioactive compounds and serve as capping agents for the nanoparticles. XRD analysis of the AgNPs indicated a high degree of crystallinity. EDX spectrum showed a strong signal attributed to Ag nanocrystals. The optimum parameters of the AgNPs were the optimum temperature of 25°C, a neutral pH, 1.0 mM concentration of AgNO3 and the reaction time of 144 hrs. AgNPs were more effective against Enterobacter cloacae ATCC13047, with an inhibition diameter of 59±1.01 mm.