A few organisms are known to grow and multiply at temperatures of 100105 o C. They belong to (a) thermophilic sulphur bacteria (b) hot spring bluegreen algae (c) methanogenic archaebacteria (d) marine archaebacteria.
Option A Thermoacidophiles (temperature and acid loving) archaebacteria are found in hot sulphur springs. Although they are microscopic, single celled organisms, they flourish under conditions which would kill higher organisms. These are aerobic bacteria and have the capacity to oxidize sulphur to H 2 SO 4 at high temperature and high acidity (pH = 2.0). Some of them are also able to reduce sulphur to H 2 S under anaerobic conditions. As a rule, they grow best between 80º and 100ºC and several species do not grow below 80ºC.
