Screening and Optimization of Silver Nanoparticles Biosynthesis by Fungi
In vitro mycosynthesis of silver nanoparticles (AgNPs) using Penicillium aurantiogresium, Penicillium roqueforti, Aspergillus niger, Verticillium chlamydosporium var. chlamydosporium, Trichoderma viride and Trichoderma longibranchiatum had been investigated. The process of silver ion reduction by either extracellular fungal filtrate or intracellular cell-free filtrate was achieved which lead to the development of an easy process for synthesis of silver nanoparticles. Upon exposure of the fungal filtrate to silver nitrate, the latter was reduced to silver nanoparticles as indicated by a color change observed and characterized by UV-visible spectroscopy. The optimum experimental conditions for AgNPs synthesis were found to be a temperature of 37oC at pH of 6.0 and a substrate concentration of 2mM silver nitrate after 24 hours incubation times in dark and measured spectrophotometrically at 430 nm. Silver nanoparticles produced were characterized by various analytical techniques such as TEM, FT-IR and X-Ray analysis of both EDX and XRD. The obtained results revealed that the size of nanoparticles for all the tested fungi ranged from 8.97 to 16.73 nm with variable shapes, most of them present in spherical in nature.