Rapid Synthesis of Silver Nanoparticles by a Marine-derived Fungus Aspergillus Niger and their Antimicrobial Potentials

Recently, biosynthesis of nanoparticles has received attention due to an increasing need of developing rapid, simple and ecofriendly protocol. Pathogenicity of some of the organisms and lengthy reaction are the drawbacks involved with biosynthesis. We describe a simple protocol for rapid synthesis of silver nanoparticles through biological route using a marine-derived fungus Aspergillus niger. Silver nanoparticles biosynthesis could be achieved within 3 minutes (which otherwise generally takes about 24h) by altering pH of the reaction mixture. Silver nanoparticles biosynthesized at different pH have been observed to have antimicrobial potentials against four test bacteria (viz. Bacillus megaterium, Proteus vulgaris, Staphylococcus aureus and Shigella sonnei). Further, combined effect of Gentamicin and biosynthesized silver nanoparticles and effect of culture condition (pH) on antimicrobial effect have also been studied. Based on the findings it is concluded that the present study provides a solution to the drawbacks involved in biosynthesis of silver nanoparticles, an ecofriendly approach. It is envisaged that the biosynthesized silver nanoparticles alone, or their combination can be potentially used as effective agents against pathogens.