An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment. Anaerobes may be unicellular or multicellular. Most fungi are obligate aerobes, requiring oxygen to survive. However, some species, such as the Chytridiomycota that reside in the rumen of cattle, are obligate anaerobes; for these species, anaerobic respiration is used because oxygen will disrupt their metabolism or kill them. Deep waters of the ocean are a common anoxic environment.
Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.
Atopobium is a genus of Actinomycetota, in the family Coriobacteriaceae. Atopobium species are anaerobic, Gram-positive rod-shaped or elliptical bacteria found as single elements or in pairs or short chains.
Cryptobacterium is a genus of Actinomycetota, in the family Coriobacteriaceae. Up to now there is only one species of this genus known.
Sporohalobacter are a genus of anaerobic bacteria belonging to the family Haloanaerobiaceae. The organisms are spore-forming bacteria that grow in hypersaline environments.
Anaerobacter is a genus of Gram-positive bacteria related to Clostridium. They are anaerobic chemotrophs and are unusual spore-formers as they produce more than one spore per bacterial cell. They fix nitrogen. Their G+C content is 29%. Only one species of this genus has been described.
Desulfovirgula is a genus of sulfate reducing, anaerobic, endospore-forming, Gram-positive, thermophilic, motile, rod-shaped bacteria, isolated from an underground mining site in an area of Japan characterized by high geothermal activity.
Clostridium ljungdahlii is an anaerobic, rod-shaped, motile, endospore-forming, gram-positive bacterium. It is named after the biochemist Lars G. Ljungdahl. When originally harvested from the waste matter of animals, it tended to produce acetate with respect to ethanol, but a major undertaking to increase the ethanol-to-acetate ratio was initiated. A 1993 publication by researchers from the University of Arkansas, in cooperation with Oak Ridge National Laboratories, showed results from a series of continuous reactor studies caused a major change in the bacterium's preference for ethanol production, which increased from <0.1 g/L to 1.8 g/L in a continuous stirred tank reactor.
Pigmentiphaga litoralis is a gram-negative, oxidase and catalase-positive, facultatively anaerobic non-spore-forming, non-motile, rod-shaped bacterium from the genus Pigmentiphaga, which was isolated from a tidal flat sediment in the South China Sea in China. Colonies of P. litoralis are yellow colored.
Propionivibrio is a genus of gram-negative, chemoorganotrophic, non-spore-forming bacteria from the family of Rhodocyclaceae which belongs to the class of Betaproteobacteria.
Propionivibrio limicola is a gram negative, oxidase- and catalase-negative anaerobic, fermentative, non-spore-forming, mesophilic, rod-shaped, motile bacterium from the genus of Propionivibrio which has the ability to degrade hydroaromatic compounds.
Propionivibrio pelophilus is a bacterium from the genus of Propionivibrio. Propionibacter pelophilus has been reclassified to Propionivibrio pelophilus.
Desulfococcus biacutus is a Gram-negative and strictly anaerobic bacterium from the genus of Desulfococcus which has been isolated from anaerobic digestor sludge in Germany.
Clostridium isatidis is a Gram-positive, anaerobic and moderate thermophilic bacterium from the genus Clostridium.
Caldicoprobacter oshimai is a Gram-positive, extremely thermophilic, anaerobic, xylanolytic and non-motile bacterium from the genus of Caldicoprobacter which has been isolated from faeces of sheep from the farm at the University of Georgia in the United States.
Acidiferrobacter is an acidophilic, thermotolerant, and facultatively anaerobic genus of bacteria with one known species. This genera has been included in new order called Acidiferrobacterales in 2015. A. thiooxydans has been isolated from refuse from a coal mine from Calloway County, Kentucky, in the United States.
Hallella is a Gram-negative, non-spore-forming, anaerobic and non-motile genus of bacteria from the family of Prevotellaceae with on known species. Hallella is named after the American microbiologist Ivan C. Hall. Hallella seregens has been isolated from a gingival crevice of a patient.
Haloimpatiens massiliensis is a Gram-positive, anaerobic and rod-shaped bacterium from the genus of Haloimpatiens which has been isolated from the gut of an infant from Marseille.
Trichococcus ilyis is a bacterium from the genus Trichococcus which has been isolated from sludge from an anaerobic sulfate-reducing bioreactor from Jiangsu.
Aminomonas is a genus of bacteria from the family of Synergistaceae with one known species. Aminomonas paucivorans has been isolated from an anaerobic lagoon of a dairy wastewater treatment plant.
