Extremophiles: How Smart Are the Cells to Cope with the Environment?

Extremophiles, or extreme-conditions-loving microorganisms, have been around since the time Earth formed and started cooling down. From the formation of the first organic molecules to the first life form as an independently replicating cell, extremophiles have seen it all and been there too. This chapter focuses on the adaptations, especially those of proteins, of various types of extremophiles that still exist at those extreme corners of the planet, ultimately leading to the concept of polyextremophiles. There is no doubt that enzymes purified from such organisms, dubbed extremozymes, are incredibly useful not only in various biotechnological and molecular biology techniques but also for the bioremediation of contaminated or polluted regions. Nevertheless, it is always interesting to understand how they withstand such severe conditions and provide us with new insights about the origin of life in this universe, on this Earth or any other planet.