the first of the "pyrobaculum" species to be genetically sequenced, "p. aerophilum" (rod-shaped, 3–8 * 0.6 µm), has a rare characteristic for an archaeon because it is capable of aerobic respiration (aerophilum = "air-loving"). this is evident from the fact that the archaeon grew only in the presence of oxygen when nitrate was absent. it produces colonies that are round and greyish yellow. it utilizes both organic (maximal cell densities were observed with complex organics such as yeast extract, meat extract, tryptone, and peptone as substrates) and inorganic compounds during aerobic and anaerobic respiration. also, use of elemental sulphur for growth was observed. further, "p. aerophilum" grows between 75 and 104 °c with an optimal growth temperature at 100 °c.