Extracellular Biosynthesis of Silver Nanoparticles Using Sphingomonas paucimobilis, Serratia Sp. and Pseudomonas aeruginosa and Their Antimicrobial Activity

Synthesis of silver nanoparticles (AgNPs) by microorganism is emerging as an important branch of nanotechnology due to its ecofriendly, safe, and cost-effective nature. Cell-free culture supernatants of three bacteria Sphingomonas paucimobilis, Serratia sp. and Pseudomonas aeruginosa have been used to synthesize silver nanoparticles (AgNPs). The AgNPs were characterized using atomic force microscopy. The sizes of the AgNPs 91.74nm, 93.39n m and 93.55n m respectively. The antimicrobial activity of the synthesized silver nanoparticles was tested using both gram positive as well as gram negative bacteria, Staphylococcus aureus, Klebsiella pneumoniae, and Streptococcus pyogenes, also tested using Candida albicans respectively. In this study, AgNPs have the highest antibacterial and antifungal effect against all microorganisms and the zone of inhibition increased with the increase of silver nanoparticles concentration.