Being a microbiologist requires a student to learn (memorize) a number of "facts". I was, back then, quite good at learning and memorizing "facts" while in other biology courses so the medical microbiology course I took in my undergraduate schooling was fun for me.
One of the first "facts" we were expected to know was that all microbial life could be killed if subjected to 121 degrees Celsius (250 degrees Fahrenheit). If you want to sterilize (kill all known life) a liter of liquid media then putting the media in an autoclave (a very expensive pressure cooker) was essential. The media being liquid if subjected to temperatures above 100 degrees Celsius (100 degrees Celsius or 212 degrees Fahrenheit is the boiling point for water) would boil away so to get the liquid above 100 degrees Celsius required pressurizing the media. So the second "fact" I needed to know was that one liter of liquid media subjected to 15 psi (pounds per square inch) of pressure at 121 degrees Celsius for 15 minutes using steam heat would kill all microbial life.
Now all that has changed. Researchers K. Kashefi and D.R. Lovley from the University of Massachusetts have discovered a microbe that is able to not only survive at 121 degrees Celsius but it also can grow at that temperature (Extending the Upper Temperature Limit for Life, 15 August 2003, Vol. 310. Science). In fact they used an autoclave to grow the organisms. The organism they call Strain 121 was isolated from the Northeast Pacific Ocean near a "black smoker" hydrothermal vent called Finn in the Mothra hydrothermal vent field. Other researchers from the University of Washington lead by J. Baross obtained the organism about 1.5 miles down in the ocean by this black smoker with a remote controlled submarine.
This organism is very interesting. First of all it uses iron like we use oxygen as a means of generating energy. It grows fastest at 103 degrees Celsius with a generation time of about one hour (generation time is the time a population of living organisms need to reproduce). At 121 degrees Celsius the organisms had a generation time of 24 hours. The organism is round or coccoid in shape with a diameter of about 1 micron. It was determined to be a member of the Archaea. Archaea are single-celled microbes similar to, but not quite, bacteria. They often live amid extreme heat, cold, pressure, salinity, alkalinity, and/or acidity. Further analysis indicated that Strain 121 is closely related to Pyrodictium and Pyrobaculum that are also members of the Archaea.
In case you are worried this organism does not grow very well at temperatures
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