ABSTRACT

Chemical or biological methods are involved for the synthesis of nanostructured building blocks and subsequently assembled into final forms of nanomaterials in the bottom-up approach. The physical approaches for the synthesis of nanomaterials requires huge consumption of energy to maintain high temperature and pressure during synthesis; however, bioprocesses take place under normal atmosphere and temperature that save energy. Green synthesis methods employing either biological microorganisms or plant extracts have emerged as a simple, economic and eco-friendly method. The green synthesis method involves selection of three main steps: solvent medium, environmentally benign reducing agent and non-toxic substances for nanoparticle stability. Plant-mediated biological synthesis of nanoparticles is gaining importance due to its simplicity, eco-friendliness and extensive antimicrobial activity. The microbial synthesis technique for nanoparticles have been explored and most widely used for the synthesis of nanoparticles such as silver, gold, platinum, titanium dioxide and zinc oxide nanoparticles.