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.