Microbial Bioremediation of Metals and Radionuclides
Environmental Technology and Engineering
Published Online: 15 JAN 2013
Copyright © 2002 John Wiley & Sons, Ltd
Encyclopedia of Environmetrics
How to Cite
Gadd, G. M. 2013. Microbial Bioremediation of Metals and Radionuclides. Encyclopedia of Environmetrics. 4.
- Published Online: 15 JAN 2013
Microorganisms possess a variety of mechanisms that effect changes in metal speciation and mobility. As well as being components of natural elemental cycles for metals, these processes may be exploited in environmental biotechnology and almost all metal-microbe interactions have been examined for removal, recovery, or detoxification of metal, organometal, metalloid, or metal radionuclide pollutants. Metal mobilization can be achieved by, for example, protonation, chelation, chemical and redox transformations, while immobilization can occur by precipitation or biomineralization, or by sorption, uptake, and intracellular sequestration. Redox reactions can mobilize or immobilize metals depending on the metal species involved. Solubilization may enable metal removal from solids such as soils, sediments, dumps, and industrial and mining wastes. Metal immobilization results in insoluble forms of low bioavailability. Biotechnological applications of microbial systems in bioremediation may provide alternatives or adjuncts to conventional treatment methods for solids, and contaminated effluents and wastewaters. While much research is laboratory-based, there are many developments to pilot/demonstration scale, with several in situ and ex situ large-scale processes in successful operation. Metal removal/transformation processes are also intrinsic components of traditional means of water/sewage treatment as well as reed bed, lagoon, and wetlands technologies.