Cyanobacteria as a bioreactor for synthesis of silver nanoparticles-an effect of different reaction conditions on the size of nanoparticles and their dye decolorization ability.

The green synthesis of metallic nanoparticles has paved the way for improving and protecting the environment by decreasing the use of toxic chemicals and eliminating biological risks in biomedical applications. Biological synthesis of metal nanoparticles is gaining more importance due to simplicity, rapid rate of synthesis and eco-friendliness. In the present investigation cyanobacterial (Microchaete NCCU-342) cell free aqueous extract has been used for optimizing biosynthesis of silver nanoparticles (AgNP). The optimized reaction parameters for efficient synthesis of AgNP were: biomass quantity of 80 µg/ml, pH 5.5, 60 °C temperature, duration of 60 min UV light exposure and 1 mM AgNO3 concentration. AgNP was characterized by UV-Visible Spectrophotometery, Transmission Electron Microscopy and Dynamic light scattering. The smallest nanoparticles (obtained from biomass parameter were spherical, polydisperessed and in the range of 60-80 nm) were characterized further in a degradation study of azo dye methyl red. Degradation of methyl red within 2 h was more with AgNP (84.60%) as compared to cyanobacterial extract (49.80%).