Application of Genetically Modified Microorganisms for Bioremediation of Heavy Metals from Wastewater

The prevalence of heavy metals in the aquatic environment poses a threat to the aquatic life as well as the terrestrial organisms, including humans. The long-term exposure to naturally occurring heavy metals has been reported to cause severe health complications in human beings. Thus, the heavy metals have been recognised as one of the most hazardous pollutants prevalent in the environment that disturbs and damages the ecosystem. Various physical and chemical methods are available for the remediation of contaminants such as heavy metals, PCBs, PAHs, etc., from the polluted sites. However, these techniques are associated with several limitations like higher costs and unsustainable nature. Thus, alternative approaches like genetically modified organisms are now being explored to achieve efficient bioremediation. The present study aims at exploring the utilisation of genetically modified microorganisms (GMMs) for heavy metal bioremediation from wastewater. The principle of bioremediation and various in situ and ex situ techniques for treatment of heavy metal polluted water has been discussed. This is followed by an elaboration of the GMMs and their use for heavy-metal remediation from wastewater. The chapter provides an insight into the status of heavy metal pollution in water in India, sources and toxicity of heavy metals. Finally, the recent case studies on the use of GMMs for remediation of heavy metals have been presented. In view of the present literature, it can be concluded that genetic engineering holds great potential for enhancing the bioremediation rate and removal of target contaminants from the wastewater.