Abstract
Extremophiles are group of microorganisms that possess ability to tolerate and live under the extremes of physico-chemical, geological and nutritional conditions. Such microorganisms are evolutionary relics and have evolved adaptation strategies at cellular, biochemical and molecular levels. They produce enzymes that are capable to maintain stability and function under the multitudes of extremities. These organisms also produce variety of other molecules and metabolites, such as extremolytes and surface-active compounds to protect against extremes of salinity, pH, pressure, temperatures and solar radiation. Investigations on these microorganisms can further open new avenues and opportunity for research and biotechnological applications in the areas of waste water treatment, bio-plastics, biofuel, cosmetics, agriculture, food and pharmaceuticals. Further, extremophiles have potential roles to play in bioremediation, astrobiology and biorefinery.