The study of strictly anaerobic microorganisms

This chapter describes the apparatus and methodology for growth, isolation, scale-up of the most stringent anaerobes and the isolation of oxygen-labile biomolecules. Methods described in the chapter are applicable to methanogenic Euryarchaeota, non-methanogenic hyperthermophiles within both the Euryarchaeota and Crenarchaeota, and hyperthemophilic bacteria within the Thermotogales. These methods are also applicable to “nonextremophiles,” such as the iron-reducing and sulfate-reducing bacteria as well as other obligate anaerobes within the bacteria. These anaerobic micro-organisms are ubiquitous in the environment and occur in a large range of “extreme” habitats that include anoxic sewage digestors, mammalian, ruminant and termite digestive tracts, polar lakes and tundra, geothermal submarine vents, calderas and hot springs, deep sea sediments, and deep subsurface rock. Unlike facultative anaerobes and oxygen-tolerant anaerobes, many obligate anaerobes require stringent anaerobic conditions to maintain viability. This is achieved by using oxygen-free gases to prepare anoxic medium with the addition of chemical reducing agents to achieve a low redox potential. Specialized glassware and vessels are utilized to maintain reduced anoxic conditions during growth.