Goldie Oza, Sunil Pandey, Ritu Shah, Madhuri Sharon
Use of microorganisms for the synthesis of nanoparticles is in the limelight of modern nanotechnology. Using Pseudomonas aeruginosa, biosynthesis of silver nanoparticles was investigated. Apart from standardizing the best parameter for the synthesis of silver nanoparticles, efforts were directed towards assessing the reducing agent involved in reduction of silver ion to silver nanoparticles. The involvement of nitrate reductases as reducing agent was confirmed by biochemical assay. The nitrate reductase activity got reduced from 0.9876 mmole/min/ml to 0.3233 mmole/min/ml after bio fabrication of silver nanoparticles. The most influential parameters for the synthesis of silver nanoparticles were found to be 100°C and pH 10 that can very effectively biosynthesize silver nanoparticles from a 100 ppm aqueous solution of AgNO3. The silver nanoparticles exhibited maximum absorbance at 450 nm in UV–Vis spectrum. The XRD spectrum of silver nanoparticles exhibited 2θ values corresponding to the silver nanocrystals. TEM micrographs revealed the formation of well-dispersed silver nanoparticles of 20-50 nm. The silver nanoparticles showed maximum antimicrobial activity against Pseudomonas aeruginosa, followed by Staphylococcus aureus and minimum anti-microbial activity was noted against Escherichia coli. It was interesting to note that Pseudomonas aeruginosa that biosynthesized the silver nano particle was most affected by its antibacterial activity
