Chapter 13 - Biological synthesis of metal nanoparticles by microorganisms: a sustainable approach

Abstract

Nanotechnology deals with substances with at least a dimension within the size of one–one hundred nm. The nanosize affects distinctive physical and chemical properties, which vary from its source, i.e., substance with the larger size. Different strategies toward nanoparticles synthesis include biological, chemical, and physical. Though the chemical and physical methods ensure a continuous supply of nanoparticles as they are their major sources, they have adverse environmental impacts. This features the necessity of sustainable and green synthesis. Such synthesis of nanoparticles is ensured by potent natural sources of reductants like plants and microorganisms because of their low cost, eco-benign, and fascinating characters. The microorganisms are known for their capability to biosorb and bioreduce metal ions to corresponding nanoparticles. The microorganisms-mediated metal nanoparticles synthesis may be either intracellular or extracellular. The synthesized metal nanoparticles have diverse functions. The ease of handling and cultivation of microbial cells ensures the safe and efficient utilization of these biological agents in metal nanoparticle synthesis. So as to empower a wider pertinence of microorganism intervened synthesizing of nano-sized particles as a substitute to physical and chemical methodologies of synthesis, some hurdles still need to be overcome. However, the techniques used in microbial mediated metal nanoparticles synthesis are simple, easy to execute, cheap and eco-friendly, and these techniques can contribute to sustainable development goals.