SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES BY RHIZOPUS STOLONIER

Biological synthesis of silver nanoparticles by using fungi is reported here. The present study is on screening of filamentous fungi for the production of silver nanoparticles extracellularly. Eight fungi, Rhizopus.spp, Aspergillus terreus, A.flavus, A.niger, A.clavatus, Acremonium.spp, A.rutilum, Trichoderma.sp. have been screened for the production of silver nanoparticle. The fungal filtrates of the above said isolates were subjected to silver nitrate. After incubation, visual observation of brown color is an indication of silver nanoparticle production. Of the eight fungi, only one Rhizopus stolonifer showed maximum absorbance at 422nm. Parametric optimization study showed maximum absorbance at 40oC and pH 7.0. Further characterization was made by UV-Visible absorption spectroscopy which shows maximum absorption at 422 nm, Transmission Electron Microscope (TEM) revealed the formation of spherical nanoparticles with size ranging between 5 to 50 nm. Energy Dispersive Spectroscope (EDS) shows the optical absorption peak at 3kev, Fourier Transform Infrared (FT-IR) shows the bands at 1645(1), 1537(2) and 1454(3) cm-1.