Chapter 12 - Recent Developments in Green Synthesis of Metal Nanoparticles Utilizing Cyanobacterial Cell Factories

Abstract

Nanoparticles (NPs) serve as connecting links between molecular structures and macromolecules/bulk materials, hence they are of great scientific interest. Metallic NPs find applications in various fields, such as cosmetics, electronics, packaging, coatings, and biotechnology. In nanotechnology, synthesis of metallic NPs is an active area of application research. There are numerous physical as well as chemical methods of nanoparticle synthesis, but many of these methods are expensive or use toxic substances and hence are not preferred. An alternate, feasible, and ecofriendly way to synthesize metallic NPs is biological methods employing microbes and plants. Recently use of microalgae has been emphasized in biological systems for synthesis of metallic NPs. Several microalgae have excellent potential for bioremediation of toxic metals and their conversion into more amenable forms, and this makes them desirable candidates for biological methods. Different microorganisms employ extracellular or intracellular pathways for biosynthesis of NPs. Biological synthesis of metallic NPs can be done by using whole cell masses of bacteria, fungi, and algae or using culture supernatant or cell extract of microorganisms. Cyanobacteria constitute the most promising group of photosynthetic microorganisms, and produce a plethora of natural compounds of industrial and pharmaceutical importance. Additionally, the cell extract of cyanobacteria contains numerous biomolecules which facilitate synthesis and stabilization of NPs. This chapter presents the advancements achieved so far in the rapidly growing field of green synthesis of NPs using cyanobacteria.