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What are Extremophiles?

written by: Rafael•edited by: dianahardin•updated: 7/14/2009

Certain organisms live where others can’t. They thrive in hostile conditions where others would not survive. These organisms are called extremophiles because they live under extreme conditions. The majority are types of archaea and bacteria. And they are important for research.

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    What are Extremophiles?

    Recently, a new microorganism was discovered in the McMurdo Dry Valleys, under the Taylor Glacier in Antarctica. What is amazing about this new microorganism is that it thrives with no sunlight and oxygen, at very low temperatures.

    The Dry Valleys of Antarctica, where the microbes were found, is one of Earth’s most extreme environments. And there, a microorganism lives. These are the extremophiles, microorganisms that can live under extreme conditions. There are microorganisms that, in contrast with the one found in Antarctica, can live in very hot environments such as in the Grand Prismatic Spring of the Yellowstone National Park or very near a volcano mouth.

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    Where do Extremophiles Grow?

    Extremophiles have been discovered in a great variety of extreme environments. In fact they are classified by the conditions in which they live. So if you have a bacterium living at high temperatures (60–80 °C) then you have a thermophile, and species than can exist in environments under pH 3 are classed as acidophiles. Radioresistant strains are resistant to radiation, physocrophiles (lower temperatures), cryophiles (very low temperatures), osmophiles (can live at high concentration of sugars), and metalotolerant (live on high levels of dissolved heavy metals). Many can thrive in a combination of extreme conditions for example no oxygen and high temperatures.

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    Extremophiles Research

    Research on extremophiles is important for a variety of reasons. To begin with, extremophiles may hold the key to understand evolution in earth life’s early days. Before live started as we know it today, earth conditions were very harsh. There was no oxygen, there was plenty of sulfur compounds, hydrogen, frequent electrical storms, etc. This cocktail was in fact very extreme for life as we know it today. But it is precisely under these extreme conditions that lives was born and proceeded to continue until today. In addition, research on extremophiles may have very interesting practical application in many industrial systems. For example, researchers at Idaho National Laboratory have developed an enzyme that works under high temperatures and high acidity levels (a thermoacidophilic xylanase) to breakdown cellulosic material for bioenergy applications or a thermoalkaliphilic enzyme (catalase) for industrial applications (catalyzes the breakdown of hydrogen peroxide into oxygen and water).

    Other studies on extremophiles involves research on organisms from the deep ocean and their role in production of gas, organisms that grow on nuclear fuel storage, microorganisms that amid aid in remediating mine acid drainage or in solubilizing metals in mining.

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    Mikuki et al. 2009. A Contemporary Microbially Maintained Subglacial Ferrous 'Ocean'," Science, 324. April 17, 2009.