------------------------------------------------------------------ Maximum Organism Activity or condition temperature, °C ------------------------------------------------------------------ 73 Thermophilic organisms Growth (P³² metabolism) ------------------------------------------------------------------ 73 _Phormidium_ (alga) Acclimatized ------------------------------------------------------------------ 70 to 73 _Bacillus calidus_ Growth and spore germination ------------------------------------------------------------------ 70 to 74 _Bacillus cylindricus_ Growth and spore germination ------------------------------------------------------------------ 70 to 75 _Bacillus tostatus_ Growth and spore germination ------------------------------------------------------------------ 80 _Bacillus Cultured in laboratory stearothermophilus_ ------------------------------------------------------------------ 83 Sulfate-reducing Found in a well bacteria ------------------------------------------------------------------ 89 Sulfate-reducing Found in oil waters bacteria ------------------------------------------------------------------ 65 to 85 Sulfate-reducing Cultured in laboratory bacteria ------------------------------------------------------------------ 89 Micro-organisms Found in hot springs ------------------------------------------------------------------ 95 _Bacillus coagulans_ In 80 min. sporulation activation ------------------------------------------------------------------ 110 _Bacillus coagulans_ In 6 min, sporulation activation ------------------------------------------------------------------ 104 _Desulfovibrio Grow and reduce sulfate desulfuricans_ at 1000 atm ------------------------------------------------------------------ Table V.—_Extreme Temperature Limits of Survival_