Abstract: The present invention relates to a novel hyperthermophile, in particular, to a hyperthermophile belonging to a novel genus isolated from compost by fermenting organic wastes at a temperature of 85° C. or more which is capable of growing at 80° C. or more (Caldothrix satsumae). The hyperthermophile of the present invention does not multiply at 50° C. or below, but grows and multiplies vigorously at 70 to 85° C. It is non-spore forming, gram-negative, and an absolutely aerobic rod. The hyperthermophile is useful as a fermenting microbe when organic wastes are fermented at high temperatures to produce compost. Further the hyperthermopile can be utilized for the production of heat resistant enzymes.