Bio‐fabrication of silver nanoparticles by Pseudomonas aeruginosa : optimisation and antibacterial activity against selected waterborne human pathogens

Multiple drug resistance and treatment of contaminated water has become a serious issue in past years. Silver nanoparticles (AgNPs), being bactericidal, non‐toxic, cheap and environment friendly behaviour, have drawn attention to overcome these problems. This study has been designed to synthesise AgNPs from Pseudomonas aeruginosa. AgNPs formation was confirmed by colour change and UV–vis spectroscopy. Furthermore, Fourier transform infrared spectroscopy peaks demonstrated the presence of capped proteins as reducing and stabilising agent. Transmission electron microscopy micrograph revealed spherical shape AgNPs with the size ranging between 10 and 20 nm. Antibacterial activity of AgNPs was evaluated against the most prevalent waterborne pathogens enterohaemorrhagic Escherichia coli and Salmonellae typhimurium. Moreover, the antibacterial activity of AgNPs was tested for the treatment of contaminated water which showed attenuation in bacterial load within 8 h as demonstrated by growth kinetics data. Furthermore, AgNPs did not exhibit haemolytic effects on human red blood cells (RBCs) even at 100 mg L⁻¹ concentration of AgNPs. The results herein suggest that AgNPs synthesised by P. aeruginosa under optimised conditions exhibit microbicidal property against waterborne pathogens and having no toxic effect on human RBCs. These AgNPs could be employed for treatment of contaminated water after process optimisation.Inspec keywords: silver, nanoparticles, nanobiotechnology, nanofabrication, microorganisms, antibacterial activity, water treatment, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, blood, cellular biophysicsOther keywords: biofabrication, silver nanoparticles, Pseudomonas aeruginosa, optimisation, antibacterial activity, waterborne human pathogens, multiple drug resistance, contaminated water treatment, colour change, UV‐vis spectroscopy, Fourier transform infrared spectroscopy, capped proteins, reducing agent, stabilising agent, transmission electron microscopy micrograph, enterohaemorrhagic Escherichia coli, Salmonellae typhimurium, growth kinetics, human red blood cells, microbicidal property, process optimisation, Ag