Alkaliphiles are a class of extremophilic microbes capable of survival in alkaline environments, growing optimally around a pH of 10. These bacteria can be further categorized as obligate alkaliphiles, facultative alkaliphiles and haloalkaliphiles.
Bacillus subtilis, known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants and humans. A member of the genus Bacillus, B. subtilis is rod-shaped, and can form a tough, protective endospore, allowing it to tolerate extreme environmental conditions. B. subtilis has historically been classified as an obligate aerobe, though evidence exists that it is a facultative anaerobe. B. subtilis is considered the best studied Gram-positive bacterium and a model organism to study bacterial chromosome replication and cell differentiation. It is one of the bacterial champions in secreted enzyme production and used on an industrial scale by biotechnology companies.
Bacillus halodurans is a rod-shaped, Gram-positive, motile and spore-forming bacterium found in soil. In a genomic comparison with Bacillus subtilis, B. halodurans strain C-125 - originally an unclassified Bacillus strain - was found to contain unique genes and sigma factors that may have aided its adaptation to more alkaline environments.
Bacillus atrophaeus is a species of black-pigmented bacteria. Its type strain is NRRL NRS-213. B. atrophaeus strains have been used extensively in biomedicine as indicator strains for heat- and chemical-based decontamination regimens. Most of the strains in use are derivatives of a lineage of B. atrophaeus that originated at Camp Detrick in the 1950s, where many modern biocontainment procedures were developed. B. atrophaeus has historically been known by several other names, including B. globigii and B. subtilis var. niger. Modern phylogenetic analyses using multiple genetic methods have placed B. atrophaeus close to B. subtilis. Its original and still most prominent use is as a surrogate organism for pathogenic B. anthracis, beginning in the U.S. bio-weapons program, as its pigmentation readily facilitated discrimination from non-pigmented background organisms in environmental samples. Subsequent genomic and phenotypic analysis of strains derived from the Camp Detrick isolates revealed that they had been deliberately selected for strains that exhibited elevated rates of sporulation.
Bacillus clarkii is a facultative anaerobe bacterium. It is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria.
Bacillus gibsonii is a facultative anaerobe bacterium. It is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria.
Bacillus horikoshii is a facultative anaerobe bacterium. It is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria.
Bacillus pseudalcalophilus is a facultative anaerobe bacterium. It is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria.
Bacillus pseudofirmus is a facultative anaerobe bacterium. It is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria.
Oceanobacillus iheyensis is a bacterium, the type species of its genus. It is a deep-sea species, having been isolated from a depth of 1,050 metres (3,440 ft), and is extremely halotolerant and alkaliphilic. Its type strain is HTE831. Oceanobacillus iheyensis HTE831 is an alkaliphilic and extremely halotolerant Bacillus-related species isolated from deep-sea sediment.
Lysinibacillus fusiformis is a gram-positive, rod-shaped bacterium of the genus Lysinibacillus. Scientists have yet to completely characterize this microbe's pathogenic nature. Though little is known about this organism, several genome sequencing projects for various strains of L. fusiformis are currently underway.
Bacillus horti is a species of Gram-negative alkaliphilic bacillus. Its cells are strictly aerobic rods that produce subterminally located ellipsoidal spores. Its type strain is K13T.
Anoxynatronum sibiricum is a Gram-positive, saccharolytic, anaerobic, alkaliphilic bacterium from the genus of Anoxynatronum which has been isolated from the Baikal lake.
Alkalibacter saccharofermentans is a Gram-positive, obligately anaerobic, alkaliphilic and non-spore-forming bacterium from the genus of Alkalibacter which has been isolated from a soda lake in the Transbaikal regio in Russia.
Fictibacillus nanhaiensis is a Gram-positive, aerobic, slightly halophilic, facultatively alkaliphilic, rod-shaped, spore-forming snd motile bacterium from the genus of Fictibacillus which has been isolated from a oyster from the Naozhou Island in China.
Fictibacillus solisalsi is a Gram-positive, rod-shaped, halotolerant, alkaliphilic and motile bacterium from the genus of Fictibacillus which has been isolated from saline soil from Shanxi in China.
Halolactibacillus halophilus is a non-spore-forming, halophilic and alkaliphilic bacterium from the genus of Halolactibacillus which has been isolated from algae from the Kanagawa Prefecture in Japan.
Salipaludibacillus agaradhaerens is a facultative anaerobe bacterium. It is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria.
Bacillus flexus is an aerobic, Gram-variable, rod-shaped, endospore-forming, oxidase positive bacteria. The endospores are ellipsoidal, located in central/paracentral, unswollen sporangia. In laboratory conditions, it produces opaque, creamish, raised margin colonies at 30 ± 2°C when incubated at 24–72 hrs. on Tryptic Soy Agar (TSA). These bacteria may be isolated from feces (poultry) and soil.
