Sustainable synthesis of silver nanoparticles using macroalgae Spirogyra varians and analysis of their antibacterial activity

In this research, silver nanoparticles (SNPs) were synthesized through bio-reduction of silver ions using the Spirogyra varians. The procedure used is simple and sustainable making it suitable for economic production of SNPs. The structure and morphology of SNPs were characterized by UV–visible spectroscopy, X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and Fourier Transform Infra-Red (FTIR). These nanoparticles indicated an absorption peak at 430 nm in the UV–visible spectrum. The crystallite average size was estimated about 17.6 nm and SEM image confirmed synthesis of relatively uniform nanoparticles. The antibacterial effect of SNPs was also tested on several micro-organisms by measuring the inhibition zone, MIC and MBC. The results confirmed that SNPs can act as a powerful antibacterial agent against various pathogenic bacteria.