under anaerobic conditions, the archaeon reduces nitrate to molecular nitrogen via the denitrification pathway. most species grow either chemolithoautotrophically by sulfur reduction or organotrophically by sulfur respiration or by fermentation. cells are rod-shaped with almost rectangular ends and are about 1.5–8 * 0.5–0.6 µm. "pyrobaculum" is motile because of peritrichous or bipolar polytrichous flagellation, and its colonies are round and grey to greenish black. the species are either faculatively aerobic or strictly anaerobic. the growth was observed on yeast extract, peptone, extract of meat, but not on galactose, glucose, maltose, starch glycogen, ethanol, methanol, formamide, formate, malate, propionate, lactate, acetate, and casamino acids.