Bioremediation of Heavy Metal Contaminated Sites

Heavy metal contamination is a global challenge causing potential health hazards to humans and biotic life due to an increase in geologic and anthropogenic activities. Heavy metals generate oxidative stress and are highly toxic even at very low concentrations, and usually bioaccumulate in food chains. Herein, we have discussed and highlighted the role of microbes and plants in bioremediation in terms of tolerance and elimination of heavy metals. The application of microbial biosorbents is ecologically friendly and economical; hence, it proved to be an effective alternative for heavy metal remediation from polluted environments. In parallel, the current chapter also addresses some fundamental concepts of plant-based remediation known as phytoremediation as well as the biochemical mechanisms associated with it. Among the introduced methods, phytoextraction, phytostabilization, and application of the PGPRs are some of the most suitable and eco-friendly techniques, which are currently considered important processes in phytoremediation. Recently, we have shifted our efforts and concepts to a broader panorama, in which particular emphasis is given to the advancements in the field of genetic engineering, metagenomics, and nanotechnology, and many of these strategies discussed are already showing great promise. Using recombinant DNA technology, whole-cell biosensors have been developed for the detection of environmental pollutants, including heavy metals. Similarly, metagenomics has played a major role in the discovery of novel genes, enzymes, pathways, and bioactive molecules involved in heavy metal resistance. Therefore, we anticipate that a discussion of existing resources and limitations will improve tools and technologies for the bioremediation of heavy metals.