Microbial application in remediation of heavy metals: an overview

Heavy metal contamination poses a menacing threat to all living forms in the natural world due to its catastrophic consequences, contributing to environmental pollution. The need for human beings increasing each day along with anthropological activity is contributing directly to the destruction of the environment with the release of a large number of heavy metals into the food chain. These metals can be accumulated in the food chains and are very extremely toxic even at low concentrations. Heavy metals aggregation can deteriorate the healthy ecosystem of the water bodies as well. One of the major concerns is the diminution and administration of the heavy metals aggregating in marine water bodies and lakes. Heavy metals are not degradable and thus tend to remain in the environment for a prolonged time period. Heavy metal aggregation can demonstrate immediate repercussions such as DNA damage, inhibition of respiration and photosynthesis, and rapid reactive oxygen species generation. Conventional or standard chemical and physical methods for remediation of heavy metals are uneconomical and lead to the production of a large magnitude of chemical waste. This shifts the focus and interest towards the utilization of microbes in remediation of heavy metals from the environment which is eco-friendly and economical. To contend with heavy metals, microorganisms have a specific mechanism such as biotransformation, biosorption, and homeostasis. The microbial system is responsive to the toxicity that is created by the heavy metals which are easily water-soluble and available in the environment. The current review article describes the sources and effects of metal ions in the environment followed by bioremediation strategies followed in their remediation. Microbial approaches in remediation of metal ions from extraterrestrial materials are depicted in the paper.