Bacillus circulans
Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Bacillus, Bacillus circulans Jordan 1890.
Hystorical synonyms:
B. amylolyticus Kellerman and McBeth (1912), B. aporrhoeus Fuller and Norman (1943), B. closteroides Gray
and Thornton (1928),
B. krzemieniewski Kleczkowska et al. (1940), B. palustris Sickles and    Shaw (1934), B. palustris var. gelaticus
Sickles and   Shaw (1934),
Vibrio perimastix Alarie and Gray (1947), B. effluens Alarie and Gray (1947), B. kellermanii Alarie and Gray
B. torquens Alarie and Gray (1947), B. latvianus Kalnins 1930.

B. circulans strains were moved to genus Paenibacillus: P. amylolyticus, P. lautus, P. pabuli, P. validus, P. glucanolyticus;
many strains are awaiting reallocation.
Gram-positive, Gram-variable or Gram-negative straight, occasionally curved rods,
2.0-4.2 x 0.5-0.8 µm, motile by peritrichous flagella.
Spores are ellipsoidal, subterminal or terminal; swelling the sporangia.
Kidney-shaped or cylindrical; and centrally located  spores were also observed.
On TSA at 30 ºC, in 2 days: colonies are 1-3 mm in diameter, opaque, cream colored,
slightly convex, with eggshell surface textures. Growth on nutrient agar is thin; in
some strains it spreads actively and may give rise to „motile colonies”. Colonies may
have irregular  margins. In nutrient broth produce low turbidity and a white, wrinkled,
thick membrane on surface.
Facultatively anaerobic. Growth temperature varies from 5-20 ºC  to 35-50 ºC (30-37
ºC optimum). Grows in pH 6-9 (optimally 7). Variable growth at pH 5 or 10 and in 7%
NaCl. NaCl, allantoin or urate are not required for growth.
Spores are numerous in soil. Isolated from sewage, food and infant bile.
Isolated from normal bee larvae (
Apis mellifera L.).
May be isolated from bee larvae (Apis mellifera L.) dead from European foulbrood or chalkbrood. Can produce wound infections,
bacteremia, septicaemia, absceses, meningitis in humans.
  1. Bîlbîie V., Pozsgi N., 1985, Bacteriologie Medicală, vol.ll, Ed. Medicală, Bucureşti.
  2. Gordon R.E., Haynes W.C., Pang C.H. (1973) – The genus Bacillus . Agriculture Handbook No. 427, U.S.D.A., Washington D.C.
  3. 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.
  4. Buiuc D., Negut M. , 2009. Tratat de Microbiologie Clinica, editia a III-a, Editura Medicala, Bucuresti.
  5. N.A. Logan and P. De Vos, 2009. Genus I. Bacillus Cohn 1872. 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, 21-127.
Positive results for catalase, hydrolysis of starch, gelatin liquefaction, beta-galactosidase, esculin hydrolysis, casein decomposition
(weak), acid production from: L-arabinose, amygdalin, L-arabitol, arbutin, cellobiose, fructose, galactose, glucose, glycerol, glycogen,
beta-gentibiose, gluconate, meso-inositol, inulin, lactose, maltose, D-mannose, melezitose, melibiose, mannitol, methyl beta-xyloside,
raffinose, sorbitol, salicin, starch, N-acetil-D-glucosamine,  sucrose, trehalose, xylitol and D-xylose.

Negative results for arginine dihydrolase, lysine decarboxylase, ornithine decarboxylase, tryptophan deaminase, egg yolk reaction,
Voges-Proskauer test, indole production, citrate utilization, H
2S production, D-arabinose dulcitol, erythritol, D- or L-fucose, sorbose and

Variable results for nitrate reduction to nitrite, hydrolysis of gelatin, hydrolysis of urea, acid production from: adonitol, D-arabitol, 2- or
5-ketogluconate, lyxose, rhamnose and ribose.
(c) Costin Stoica
Culture media
Biochemical tests
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