The goal of present work to develop silver nanoparticle utilizing red and yellow onions (Allium cepa L.) extract. Prepared AgNPs were expected to have antimicrobial activity. Biological synthesis method used to developed silver nanoparticles by using silver nitrate solution and extract of two different types’ red and yellow onions (Allium cepa L.). Developed AgNPs were characterized by UV-Vis spectroscopy, Fourier Transmission Infrared Microscopy (FTIR), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Antimicrobial activity was carried out in agar well diffusion method, against four pathogenic bacterial strains Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae.UV-Vis spectroscopy showed peaks at 418 nm for red onions AgNPs and 399 nm for yellow onions AgNPs. FTIR evaluated that amines and hydrocarbons reduction involved in silver nanoparticle stabilization. Results of SEM image demonstrated that particles were cubical and spherical in shape. The particle size distribution of red onions AgNPs were ranged in 2-9 nm, and that of yellow onions AgNPs were 3-8 nm. Further, XRD revealed different intense peaks positions at 2q. Average grain size of red onions AgNPs was 9.65 nm and yellow onions AgNPs average grain size was 7.48 nm. SEM and XRD confirmed formation of silver nanoparticles. Silver nanoparticles were successfully synthesized from both types red and yellow onions (Allium cepa L.) bulb extract. From the study, both types of biosynthesized AgNPs red and yellow onions (Allium cepa L.) were observed to showed antimicrobial potential. However, yellow onions AgNPs exhibited maximum antimicrobial activity due to its small crystal size as compared to red onion AgNPs.

Keywords:  biosynthesis, silver nanoparticles, antimicrobial