Extracellular synthesis of silver nanoparticles by Pseudomonas sp. THG-LS1.4 and their antimicrobial application

Silver nanoparticles (AgNPs) are known to have bacteriostatic and bactericidal effects. The present study highlights the extracellular synthesis of AgNPs and its antibacterial properties. The AgNPs were synthesized using Pseudomonas sp. THG-LS1.4 strain which had been isolated from soil. The AgNPs were characterized by field emission-transmission electron microscopy (FE-TEM), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, and particle size distribution (DLS). The AgNPs displayed maximum absorbance at 412 nm and were irregular in shape ranging from 10 to 40 nm. The XRD spectroscopy results demonstrated the crystalline nature of nanoparticles. The AgNPs showed antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Candida tropicalis, Vibrio parahaemolyticus, Escherichia coli and Pseudomonas aeruginosa. Furthermore, the AgNPs were also evaluated for their increased antibacterial activities with various antibiotics against Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica. Additionally, AgNPs showd biofilm inhibition activity. The biosynthesized AgNPs were found to be a potent agent against tested pathogens. More importantly, we highlight the applications of AgNPs as an antimicrobial agent.