Extracellular Synthesis of Silver Nanoparticles Using Pseudomonas aeruginosa KUPSB12 and Its Antibacterial Activity

The use of microorganisms like bacteria in the synthesis of nanoparticles emerges as an eco-friendly approach and an alternative to the chemical method. In the present investigation, we report the biosynthesis of silver nanoparticles (AgNPs) using the phosphate solubilizing bacterium Pseudomonas aeruginosa KUPSB12. Silver nanoparticles were synthesized through the reduction of aqueous Ag ion using the bacterial culture supernatants at room temperature. Synthesis of AgNPs was initially observed by color change from greenish yellow to brown which was confirmed by UV-visible spectroscopy. The silver nanoparticles were further characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopic (SEM) analyses. The synthesized nanoparticles were found to be spherical in shape with a size in the range of 50-85 nm. The synthesized AgNPs were found to have antibacterial activity against six tested pathogenic bacteria (Escherichia coli MTCC 443, Vibrio cholerae MTCC 3904, Shigella flexneri MTCC 1457, Bacillus subtilis MTCC 441, Staphylococcus aureus MTCC 3160 and Micrococcus luteus MTCC 1538). Thus, the biosynthesis of silver nanoparticles using Pseudomonas aeruginosa culture supernatant deserves to be a good candidate as an antibacterial agent.