Biogenic Metal Nanoparticles: A Sustainable Alternative to Combat Drug-Resistant Pathogens

The natural environment acts as the largest ‘bio-laboratory” of yeast, algae, fungi, plants etc., which are used as an abundant source of biomolecules. These different biomolecules play vital roles in the formation of different biogenic metals or metalloid nanoparticles. Recently, the overburden from the different microbial diseases has increased rapidly in different application sectors, viz., drug delivery, DNA analysis, cancer treatment, antimicrobial agents, water treatment and biosensor and catalysts, as a result of multipurpose work occurrence globally. The indiscriminate and arbitrary use of antibiotics in clinical practice has spurred the emergence of potentially lifethreatening multidrug-resistant pathogens. In the quest for novel antimicrobial agents, the current interest is to develop potent antimicrobial agents which exhibit broadspectrum bactericidal activity and possess a mechanism of action that does not readily favor the development of resistance. The use of nanoscale materials as bactericidal agents represents a novel paradigm in antibacterial therapeutics. Actually, eco-friendly, sustainable modern approaches, such as green syntheses of different biogenic metals or metalloid nanoparticles, are cost-effective and environment-friendly, and they are used as strong antimicrobial agents. This chapter focuses on synthesizing biogenic metal or metalloid nanoparticles with special emphasis on microbial synthesis, particularly from yeast, bacteria, algae, fungi, plants extract, etc. Finally, a detailed description of the biosynthesis mechanism using different green sources, along with their antimicrobial activity and mode of action, has been presented.