Geobacillus (Bacillus) stearothermophilus
Geobacillus stearothermophilus, Gram-stained
Taxonomy
Morphology
Growth conditions
Biochemical characters
Ecology
Pathogenicity
References
Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Geobacillus, Geobacillus stearothermophilus (Donk
,1920), Nazina, Tourova et al., 2001, type spcies of the genus.

Hystorical synonyms:
Bacillus kaustophilus Prickett (1928), Bacillus thermoliquefaciens Galesloot and Labots (1959).
Gram-positive, Gram-variable or Gram-negative rods, 1.5-2.7 / 0.6 -0.9 µm, usually
motile by peritrichous flagella. Spores are ellipsoidal, subterminal or terminal; usually
swelling the sporangia.
Colonies are circular and usually convex, and may be smooth and crenate. Growth
temperature  varies from  30-45 ºC  to  65-75 ºC. Most strains grow in the range 40-70
ºC. Grows at pH 6-8 and in 1-5% NaCl, not in 7% NaCl. Aerobic, does not grow
anaerobically.
Isolated from soil, hot springs, desert sand, arctic waters, ocean sediments, food,
and compost. Spores occur in soil. Vegetative growth is rapid in many foods of pH
above 5.0 if held at an appropriate elevated temperature. Spores are destroyed in
15-18 minutes at 121 ºC wet heat and in 20 min
utes at 180 ºC dry heat. Inhibited by
0.001% lysozyme.
Unknown (none).
  1. Gordon R.E., Haynes W.C., Pang C.H. (1973) – The genus Bacillus . Agriculture Handbook No. 427, U.S.D.A., Washington D.C.
  2. Buchanan R.E., Gibbons N.E., Cowan S.T., Holt J.G., Liston J., Murray R.G.E., Niven C.F., Ravin A.W., Stanier R.W. ( 1974) –  
    Bergey’s Manual of Determinative Bacteriology, Eight Edition, The Williams & Wilkins Company, Baltimore.
  3. Bîlbîie V., Pozsgi N., 1985, Bacteriologie Medicală, vol.ll, Ed. Medicală, Bucureşti.
  4. Logan N. A., 2005. Bacillus anthracis, Bacillus cereus, and other aerobic endospore-forming bacteria. In: Boriello S.P., Murray P.R.,
    Funke G. (Ed),Topley & Wilson’s Microbiology & Microbial Infections.Bacteriology, Vol. 2, pp. 922-952.
  5. Niall A. Logan, Paul De Vos and Anna Dinsdale 2009.Genus VII. Geobacillus Nazina, Tourova, Poltaraus, Novikova, Grigoryan,
    Ivanova, Lysenko, Petrunyaka, Osipov,  Belyaev and Ivanov 2001. In: (Eds.) P.D. Vos, G. Garrity, D. Jones, N.R. Krieg, W. Ludwig, F.
    A. Rainey, K.-H. Schleifer, W.B. Whitman. Bergey’s Manual of Systematic Bacteriology, Volume 3: The Firmicutes, Springer, 144-
    160.
Positive results for gelatin hydrolysis, oxidase (most strains), starch hydrolysis, acid
production
from fructose, glucose, glycerol, glycogen, inulin, maltose, mannose,
D-melezitoze, D-melibiose, raffinose, starch, sucrose, and trehalose.

Negative results for arginine dihydrolase, beta-galactosidase (ONPG), indole
production, H
2S production, lysine decarboxylase, ornithine decarboxylase, urease,
Voges-Proskauer test, acid production from adonitol, amygdalin, arbutin,
D-arabinose, D- and L-arabitol, N-acetylglucosamine, cellobiose, dulcitol, erythritol,
D-fucose, galactose, gentibiose, gluconate, 2-ketogluconate, myo-inositol, lactose,
D-lyxose, L-rhamnose, ribose, salicin, sorbose, sorbitol, and methyl-xyloside.

Variable results for casein decomposition, catalase, utilization of citrate as a source
of carbon (positive on Christensen's medium and negative on Simmon's medium),
esculin hydrolysis, methyl red test, nitrate reduction to nitrite, acid production from
L-arabinose, D-mannitol, D-turanose and D-xylose.
(c) Costin Stoica
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Geobacillus stearothermophilus, colonies on BHI
agar incubated at 56 ºC