Bacteria in Heavy Metal Remediation and Nanoparticle Biosynthesis

Abstract

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.

Green synthesis of metal nanoparticles using microorganisms and their application in the agrifood sector

“…Small AuNPs are deposited on bacterial cell walls at pH 2.0, while larger particles could be observed in the extracellular matrix. In general, changes in solution pH are a very influential factor in appearance and structure, as well as deposition location (extracellular or intracellular) of AuNPs [ 79 ]. Extracellular AgNP biosynthesis was demonstrated using Pseudomonas DC5 and Pseudomonas CA 417 [ 11 ].…”

“…The use of bacterial cell culture supernatant to generate AgNPs of various shapes and sizes has been reported in several other studies [ 84 ]. In general, in the AgNPs biosynthesis cycle, the presence of nitrate ions in the presence of NADPH-dependent nitrate reductase enzymes (for free electron transfer) reduces the bioavailability of silver ions and ultimately causes spherical biosynthesis of AgNPs [ 79 ]. Au–Ag bimetallic NPs produced by a Deinococcus radiodurans synthesis system with a size of 149.8 nm showed the ability to decompose toxic triphenylmethane dye malachite green (MG) and convert it to the less toxic substance dimethylamino (benzophenone) [ 85 ].…”

Facile Bio-Fabrication of Ag-Cu-Co Trimetallic Nanoparticles and Its Fungicidal Activity against Candida auris

“…Still, extensive exploration is needed in this area. Nanoparticles and nano-scaled materials, particularly metallic nanoparticles, contain new and exceptional physicochemical and biological properties [ 7 , 8 , 9 , 10 ]. The practical and promising antimicrobial ability of trimetallic nanoparticles was more than the mono and bi-metallic equivalents.…”

Enhancing Microbial Pollutant Degradation by Integrating Eco-Evolutionary Principles with Environmental Biotechnology

“…These include high processing costs, increased requirements of reagents, and the undesirable generation of secondary pollutants [7]. By contrast, biological remediation (bioremediation, see Glossary) in the form of microbe-based treatments, is a cost-effective, eco-friendly, and socially acceptable way to remove pollutants such as heavy metals [8], pesticides [9], and hydrocarbons [10] from the environment. Nevertheless, while culturable bacteria were isolated from contaminated sites already 45 years ago [11], the approach of bioremediation has so far failed to provide convincible solutions in pollutant management.…”