Silver nanoparticles production by Aspergillus niger and their antibacteria efficacy against Xanthomonas citri and Ralstonia solanacearum

Aim : Nanobiotechnology is being widely applied in multidisciplinary fields including biopesticide applications. Recently, there is an increase research in the fungal mediated production of silver and copper nanoparticles. Methodology : In this investigation, the silver nanoparticles were synthesized from the isolates of industrial fungus, Aspergillus niger and their efficacy was examined using well diffusion assay against two phytopathogenic bacteria viz., Xanthomonas citri and Ralstonia sofa nacearum. The silver nanoparticles developed from Aspergillus niger cell filtrate were described through UV-Vis spectrophotometer, Transmission electron microscope (TEM) analysis and Fourier Transform Infrared Spectroscope (FTIR). Results : The production of silver nanoparticles was confirmed by visualization of peak at 420 nm in UV-Vis spectrophotometer. FTIR studies showed the protein capping of these silver nanoparticles, while TEM microphotographs showed well dispersed silver nanoparticles which are isotropic and round having size between 3-25 nm. The 20-30 mm diameter inhibition zones were formed by biosynthesized silver nanoparticles when tested against Xanthomonas citri and Ralstonia solanacearum. Interpretation : Aspergillus niger based silver nanoparticles were proved to be used against plant pathogenic bacteria due to their broad spectrum efficacy. Further studies are needed to investigate the efficacy of silver nanoparticles as antibacterial agent in vivo.