Abstract
Hypersaline habitats are present all over the globe in the form of saline soil, saline water and salted food. Some of the more famous hypersaline habitats are the Dead Sea (Jordan-Israel), the Great Salt Lake (USA), the Solar Lake and lakes at Natrun valley (Egypt), and the inland saltern of La Mala (Spain). Halophilic microorganisms can be classified into halophilic algae, bacteria and fungi, while the halophilic bacteria are further classified into extremely halophilic bacteria, moderately halophilic bacteria, moderately halophilic eubacteria and moderately halophilic archaeobacteria. Two kinds of mechanisms, known as 'salt in' and 'low salt in', are typically exhibited by halophilic microorganisms in their adaptation to high salt concentrations. Several reports have suggested that halophilic microorganisms can be polyextremophilic. Evaluating the physiology of halophilic microorganisms and their adaptation to the environment allows a better understanding of the extremophilic characteristics of the microorganisms. Halophiles have been used in a number of biotechnological applications, making them an interesting and important choice of research topic in this era of biotechnology. This review is an attempt to give a basic understanding of halophilic microorganisms, their habitats, adaptation, as well as their importance in the current biotechnological developments.