Biosynthesis, Characterization and Antimicrobial Activity of Silver Nanoparticles by Aspergillus niger Isolated from the Rotten Onion

Abstract

Present day, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this research, we had investigated extracellular biosynthesis of silver nanoparticles using A. niger, isolated from the rotten onion. The formation of silver nanoparticles in the cell filtrates was confirmed by change in the color of filtrates of cell, absorption peak between 300-600 nm in UV-VIS spectra. There was a logical relationship in the efficiencies of studied A. niger in the production of silver nanoparticles and their nitrate reductase activity. The microscopic analysis of the colonies of A. niger was done by using 0.1% congo red dye. It effectively showed the morphological structure of the fungus with Conidia and Conidiophores. Hence, 0.1% congo red dye was used to stain the fungal smear and study it under the microscope. The present study showed that A. niger have potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity.