Green biosynthesis of silver nanoparticles by freshwater cyanobacteria Nostoc spp. and evaluation of its antimicrobial activity

 Cyanobacteria are one of the important candidates in nanoparticle biosynthesis due to their ability to collect heavy metals. Therefore, the aim of this study was to produce and characterization of the specificity of silver nanoparticles by the native cyanobacterial strain of Nostoc spp.

 After culturing and molecular identification of cyanobacteria Nostoc spp., boiling and wet biomass methods were used to produce silver nanoparticles at different concentrations. Characterization of nanoparticle production were performed by optical spectroscopy, Ultraviolet (UV-Vis), Raman and Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM). As well as antimicrobial activity of silver nanoparticles was performed by antibiogram assay.

 The results of UV-Vis showed that the production of silver nanoparticles with the help of wet biomass at a concentration of 1 mM had a higher adsorption rate than the boiling method. The results of FTIR showed the successful production of silver nanoparticles using the wet biomass method at a concentration of 1 mM silver nitrate. In addition, the results of one-way analysis of variance and Tukey's test showed significant inhibitory power of silver nanoparticles against Staphylococcus aureus, E. coli and Pseudomonas aeruginosa.

 Nostoc spp., as a potential strain in the production of silver nanoparticles have unique properties and performance for use in microbial biotechnology.