Archaebacteria found in anaerobic environments such as animal intestinal tracts or sediments or sewage and capable of producing methane; a source of natural gas.

Roget 359: life, vitality, viability; animation; vital spark, vital flame, soul, spirit.    respiration, wind; breath of life, breath of one's nostrils; oxygen, air.    [devices to sustain respiration] respirator, artificial respirator, heart and lung machine, iron lung; medical devices etc. 662.    lifeblood; Archeus^†; existence etc. 1.    vivification; vital force; vitalization; revivification etc. 163; Prometheus; life to come etc. (destiny) 152.    [Science of life] physiology, biology; animal ecology.    nourishment, staff of life etc. (food) 298.    genetics, heredity, inheritance, evolution, natural selection, reproduction (production) 161.    microbe, aerobe, anaerobe, facultative anaerobe, obligate aerobe, obligate anaerobe, halophile [Micro.], methanogen [Micro.], archaebacteria [Micro.], microaerophile [Micro.].    animal etc. 366; vegetable etc. 367.    artificial life, robot, robotics, artificial intelligence.    [vital signs] breathing, breathing rate, heartbeat, pulse, temperature.    preservation of life, healing (medicine) 662.    ... show more