Extremophiles are organisms that live under extreme conditions on earth that most life forms are unable to tolerate. These conditions might be extreme heat (over 42 degrees Celsius), cold (below 4 degrees Celsius), salinity, pH, pressure or other geochemical conditions. The majority of extremophiles are microorganisms belonging to the taxonomic domain of Archaea, but some bacteria also live under extreme conditions.
Extremophiles are found in the ice of the arctic and antarctic, deserts, deep-sea vents, volcanic fissures and areas of high salinity. Modern biotechnologists have found ways to utilize many of these microorganisms, or their enzymes, in industrial processes. For example, enzymes from cryophiles or psychrophiles (cold-loving organisms) are used to enhance the cleaning power of laundry detergents in cold water. Heat-loving (thermophilic) organisms and their enzymes are probably the most highly studied extremophiles and have many uses in industrial processes and in enzyme products in the home.