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''Bacillus megaterium'' is a rod-like, Gram-positive, mainly aerobic spore forming bacterium found in widely diverse habitats.〔De Vos, P. ''et al.'' Bergey's Manual of Systematic Bacteriology: Volume 3: The Firmicutes. ''Springer'' (2009)〕〔 With a cell length of up to 4 µm and a diameter of 1.5 µm, ''B. megaterium'' is amongst the biggest known bacteria.〔 The cells often occur in pairs and chains,〔 where the cells are joined together by polysaccharides on the cell walls. In the 1960s, prior to the development of ''Bacillus subtilis'', ''B. megaterium'' was the main model organism among Gram-positive bacteria for intensive studies on biochemistry, sporulation and bacteriophages. Recently, its popularity has started increasing in the field of biotechnology for its recombinant protein production capacity.〔Bunk, B. ''et al.'' A short story about a big magic bug. ''Bioengineered Bugs'' 1:85–91 (2010)〕 ==Characteristics== ''B. megaterium'' grows at temperatures from 3 °C to 45 °C, with the optimum around 30 °C. Some isolates from an Antarctic geothermal lake were found to grow at temperatures up to 63 °C.〔 ''B. megaterium'' has been recognized as an endophyte and is a potential agent for the biocontrol of plant diseases. Nitrogen fixation has been demonstrated in some strains of ''B. megaterium''.〔 ''B. megaterium'' has been an important industrial organism for decades. It produces penicillin amidase used to make synthetic penicillin, various amylases used in the baking industry and glucose dehydrogenase used in glucose blood tests. Further, it is used for the production of pyruvate, vitamin B12, drugs with fungicidal and antiviral properties, etc.〔Vary, S. P. ''et al.'' ''Bacillus megaterium'' — from simple soil bacterium to industrial protein production host. ''Appl Microbial Biotechnol'' 76:957–967 (2007)〕 It produces enzymes for modifying corticosteroids, as well as several amino acid dehydrogenases. ''B. megaterium'' is known to produce poly-γ-glutamic acid. The accumulation of the polymer is greatly increased in a saline (2–10% NaCl) environment, in which the polymer comprises largely of L-glutamate (L-isomer content up to 95%).〔Shimizu, K., Nakamura, H. & Ashiuchi, M. Salt-Inducible Bionylon Polymer from ''Bacillus Megaterium''. Appl. Environ. Microbiol. 73:2378–2379 (2007)〕 At least one strain of ''B. megaterium'' can be considered a halophile, as growth on up to 15% NaCl has been observed.〔Khan, J. A. Biodegradation of Azo Dye by Moderately Halotolerant ''Bacillus megaterium'' and Study of Enzyme Azoreductase Involved in Degradation. ''Advanced Biotech'' 10:21–27 (2011)〕 Phylogenetically, based on 16S rRNA, ''B. megaterium'' is strongly linked with ''B. flexus'', the latter distinguished from ''B. megaterium'' a century ago, but only recently confirmed as a different species.〔 ''B. megaterium'' has some phenotypic and phylogenetic similarities with pathogens ''B. anthracis''〔Dib, E. G. ''et al.'' Nonhemolytic, Nonmotile Gram-Positive Rods Indicative of ''Bacillus anthracis''. ''Emerg Infect Dis.'' 9:1013–1015 (2003)〕 and ''B. cereus'', although itself being relatively harmless.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bacillus megaterium」の詳細全文を読む スポンサード リンク
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