By: Sauro Dasgupta, UG 3, Department of International Relations, Jadavpur University, Kolkata
Bioremediation has been an important approach to remove environmental pollutants. It is the utilization of microorganisms to degrade these pollutants.
This process is very useful and cost effective and can degrade a wide range of pollutants including petroleum hydrocarbons and Polychlorinated hydrocarbons (PCHs) and can transform toxic heavy metals to less toxic states, such as enzymatic conversion of toxic hexavalent chromium to less toxic trivalent forms.
Soils or ground water contaminated with PCBs (Polychlorinated biphenyls) or TCE (Trichloroethylene) can be treated in bioreactor by using a pure microbial culture or a mixed culture.
A fertilizer or suitable sources of nitrogen, carbon and phosphorus are added to the bioreactor before digestion at a suitable temperature. The PCBs are first degraded under anaerobic conditions and then less chlorinated PCB products are degraded aerobically in a separate fermenter.
Recently recombinant Rhodococcus and Burkholderia species that can degrade PCBs have been developed in the laboratories. Recombinant Pseudomonas can detoxify heavy metals, carbon tetrachloride and naphthalene.
Although bioremediation is a suggested method of choice for this broad applicability and low cost, yet this is not the sole answer to the enormous problems associated with environmental pollution. In the near future more environment friendly and cost efficient technologies are in the absolute need of development for handling the environmental crises across the globe in such an accelerated pace.
Some examples of bioremediation related technologies are phytoremediation, mycoremediation, bioventing, bioleaching, land farming, bioreactor, composting, bioaugmentation, rhizofiltration, and biostimulation. Microbial bioremediation uses microorganisms to break down contaminants by using them as a food source. Phytoremediation uses plants to bind, extract, and clean up pollutants such as pesticides, petroleum hydrocarbons, metals, and chlorinated solvents. Bioremediation technology is invaluable for reclaiming polluted soil and water. In the simplest terms, bioremediation is a waste management process using live organisms to neutralize or remove harmful pollutants from contaminated areas. Microorganisms are suited to the task of contaminant destruction because they possess enzymes that allow them to use environmental contaminants as a food. For bioremediation to be effective, microorganisms must enzymatically attack the pollutants and convert them to harmless products.
