Bioaccumulation and detoxification of heavy metals: an insight into the mechanism

Abstract Heavy metal pollution is a major environmental threat caused by industries like electroplating, textiles, dyes, mining, and so forth. Due to a lack of proper effluent treatment, heavy metals are directly released into the environment. Heavy metals are toxic even at low concentrations and have adverse effects on humans, animals, plants, and other organisms. Several physicochemical methods and biological methods have been adopted to sequester heavy metals from wastewater. Under biological methods, heavy metals are removed by using different microorganisms such as algae, fungi, bacteria, and plants and their derived products. Bioremediation occurs via numerous biological mechanisms like biosorption, bioaccumulation, and biotransformation. Bioaccumulation is the process in which pollutants are accumulated by the living biomass whereas in detoxification pollutants are transformed into a nonpolluting product with the help of different reactions like oxidation, reduction, methylation, and so forth. In recent years, considerable advancements have been made in the field of bioremediation by adopting bioinformatics and genetic engineering, which help in the selection and genetic manipulation of different microbial strains to enhance the heavy metal detoxification efficiency. Moreover, different types of integrated sustainable systems, such as coupling wastewater treatment with nanoparticle synthesis or biofuel production, help in the development of a low-cost system. The present chapter discusses toxic effects of various heavy metals on the environment, detoxification of these heavy metals by microorganisms, and the mechanism adopted by them. Bioaccumulation and detoxification are potential green techniques as they make the process feasible and economical.