Extracellular Biosynthesis Of Silver Nanoparticles Research Articles

Extracellular biosynthesis of silver nanoparticles by the culture supernatant of Bacillus licheniformis

Development of reliable and eco-friendly processes for synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. One of the options to achieve this objective is to use ‘natural factories’ such as biological systems. In this study, we report the synthesis of nanoparticles of silver by reduction of aqueous Ag+ ions with the culture supernatant of Bacillus licheniformis. The morphology of the nanoparticles was characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The Debye–Scherrer equation was used to calculate particle sizes and the silver nanoparticles of approximate size 40 nm were observed. The process of reduction is extracellular, which makes it an easier method for the synthesis of silver nanoparticles.

Extracellular biosynthesis of silver nanoparticles using the fungus Aspergillus fumigatus

Development of reliable and eco-friendly process for synthesis of metallic nanoparticles is an important step in the filed of application of nanotechnology. One of the options to achieve this objective is to use natural processes such as use of biological systems. In this work we have investigated extracellular biosynthesis of silver nanoparticles using Aspergillus fumigatus. The synthesis process was quite fast and silver nanoparticles were formed within minutes of silver ion coming in contact with the cell filtrate. UV–visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) micrograph showed formation of well-dispersed silver nanoparticles in the range of 5–25 nm. X-ray diffraction (XRD)-spectrum of the silver nanoparticles exhibited 2 θ values corresponding to the silver nanocrystal. The process of reduction being extracellular and fast may lead to the development of an easy bioprocess for synthesis of silver nanoparticles.