Psychrophilic Bacteria: Biodiversity, Molecular Basis of Cold Adaptation and Biotechnological Implications

The earth is a cold biosphere with a major part (> 85.0%) permanently exposed to temperatures below 5 oC. Antarctica, Arctic, high altitude mountains, glaciers and deep-sea are the major constituents of the cold biosphere. The cold biosphere provides habitats such as snow, permafrost, sea-ice, glaciers, oceanic waters and sediments, cold water lakes, soil and caves which are conducive for the survival and reproduction of life forms. Diverse microorganisms such as bacteria, archaea, yeast, fungi and algae are known to survive, divide and colonize these cold habitats and are referred to as psychrophiles. Therefore, studies on the diversity, physiology and molecular biology of psychrophilic bacteria would provide important inputs on their distribution, survival strategies and molecular basis of their adaptation to low temperature. In this review, we focused on microbial biodiversity of psychrophilic microorganisms from Antarctica, Arctic and Himalayan glaciers, on their adaptation and biotechnological applications.