Energy systems such as fuel cells and recent combustors including internal combustion engines work at lower temperatures. Recent direct-injection gasoline and diesel engines often operate at relatively low exhaust gas temperatures around 100°C, because their lean-burn combustion process uses less fuel, resulting in burned gases of lower temperatures. The exhaust gas temperatures are close to those at which hyperthermophiles and thermophiles replicate. This situation could give rise to the possibility that thermophiles might proliferate inside the exhaust pipe of internal combustion engines. The nutrient preconditions for proliferation may be sufficient, because soot contains a lot of carbon and sulfur. Air, which is also needed by aerobic microorganisms, is taken in through the intake manifold from the atmosphere and water can be produced after combustion. Aeropyrum pernix (JCM 9820) is a species that is known to proliferate well at temperatures between 80 and 100°C, close to exhaust gas temperatures. In this paper, it is shown that Aeropyrum, a type of aerobic thermophile, proliferates well by eating soot around the temperatures in the presence of only pure water and air. This fusion of artifact and life may offer the possibility of overcoming one of the weak points of internal combustion engines.