Extreme Organism

Thermophiles are the heat loving bacteria found near hydrothermal vents and hot springs. Many thermophiles use dissolved sulfur or other elements as their energy source and iron as a means of respiration. It is generally considered as one that maintains life or activity at temperatures above 40 degrees Celsius. Thermophilic microorganisms are able to survive because of their ability to produce thermophilic enzymes. Some thermophilic enzymes have been discovered that can maintain at least half of their specific activities at temperatures as high as 80 degrees or even higher temperature. However, enzymes might partially denature at high temperatures but have adaptive systems that allow them to renature once removed from extreme conditions.

http://serc.carleton.edu/microbelife/extreme/extremeheat/

http://www.biology.ed.ac.uk/research/groups/jdeacon/microbes/thermo.htm