Chapter 4 - Bacteriogenic silver nanoparticles: mechanisms and applications

Abstract

Silver nanoparticles (AgNPs) are well known for their broad spectrum of antimicrobial properties. Owing to its eco-friendly and cost-effective synthesis protocols, there is an increasing surge toward a green synthesis of AgNPs as alternatives to chemical and physical methods. Among the biogenic sources, bacteria are more preferred microorganisms to manipulate as they grow and form microbial colonies. Microbes are known to produce nanoparticles (NPs) with varied morphology and sizes; hence, they can provide a cost-effective large-scale production. In this regard, bacteria produce large quantities of extracellular as well as intracellular proteins and enzymes that can take part in the fast and sustainable synthesis of NPs. Bacteriogenic NPs possess an outer coating of bacterial biomolecules, which increases its efficiency of activity. Biomass or extracellular materials from microorganisms like Bacillus licheniformis, Pseudomonas deceptionensis, and Streptomyces anulatus are used for the synthesis of AgNPs. This chapter will focus predominantly on the synthesis of AgNPs from various types of bacteria, with their preferred physicochemical parameters and their applications in various fields.