Bacteria in Heavy Metal Remediation and Nanoparticle Biosynthesis

Biosynthesis of nanomaterials using natural and biological materials as reducing, stabilizing, and capping agents is an important field of biomaterial science, nanoscience, and nanobiotechnology. Relative to conventional approaches for the assembly of nanomaterial deploying hazardous and dangerous resources, bioinspired synthesis using bacteria has significant advantages of cost-effectiveness and eco-friendliness besides being a sustainable, nontoxic, and inexpensive option. Additionally, bacteria can be used for the bioreduction and biorecovery of heavy metal ions. Bacterial cells, as efficient biofactories, have significant ability to bioreduce metal ions that can be obtained as nanocrystals of varying morphologies and sizes. In this regard, bacteria-assisted nanoparticle synthesis and the associated parameters need to be optimized, comprehensively. The developments in nanoparticle biosynthesis domain conform to the green chemistry principles that minimize the use of hazardous materials and maximize the safety and sustainability of the nanoparticle preparation. In this review, important issues pertaining to bioaccumulation, biotransformation, and biosynthesis of metallic nanoparticles using bacteria are highlighted including the mechanistic aspects of the bacterial synthesis of nanoparticles.