Bacillus subtilis - pellicle in liquid medium & round,
opaque colonies on solid medium
Gram positive, 2.0-3.0 / 0.7-0.8 μm, motile, peritrichous flagella. Ellipsoidal or
cylindrical, central or paracentral spore (sometimes subterminal), not deforming  the
vegetative cell. Most strains do not produce significant capsular material in the
Growth temperature from 5-15 ºC to 40-50 ºC. Optimum growth temperature 28-30 ºC. Aerobic, do not grow anaerobically. Grow in
2%, 5% & 7% NaCl. NaCl is not required for growth. Agar media: colonies round or irregular;surface dull; become thick and opaque;
may be wrinkled (rugose) and may become cream-colored or brown. Features of colonies vary greatly with composition of the
medium. Colonial morphology is variable, within and between strains, and may give the appearance of a mixed culture.
Pigments, varying from cream through yellow, orange, pink and red, to brown or black, may be formed on potato or agar media
containing glucose; strains forming brown or black pigment were often formerly called
B. subtilis var. aterrimus. Strains forming
brownish-black pigment on tyrosine, and often formerly called
B. subtilis var. niger, have been split from B. subtilis as B. atrophaeus.
Broth: dull, wrinkled pellicle; little or no turbidity. Growth active at pH 5.5-8.5 and in 7% NaCl.
B. subtilis subsp. inaquosorum is facultatively anaerobic on TGY agar or broth. Growth in 10% (w/v) NaCl occurs after 72 h. Growth in
the presence of 0.001% (w/v) lysozyme is variable.
Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Bacillus, Bacillus subtilis (Ehrenberg) Cohn 1872
Smith et al.,1946. 3 subspecies:
B. subtilis subsp. subtilis Nakamura, Roberts & Cohan 1999, phenotypically similar to Bacillus atrophaeus and distinguishable from
that species only by the pigmentation of the latter (brownish-black pigment production on tyrosine agar). Not distinguishable from
, B. subtilis subsp. spizizenii and B. vallismortis by conventional phenotypic tests.
B. subtilis subsp. spizizenii Nakamura, Roberts & Cohan 1999, phenotypically indistinguishable from B. subtilis subsp. subtilis, the
type strain was isolated from Tunisian soil.
B. subtilis subsp. inaquosorum Rooney, Price, Ehrhardt, Swezey and Bannan 2009. Closely related to B. subtilis subsp. spizizenii,
differentiated by gene sequence analysis, m/z 1120.8 biomarker (MALDI-TOF MS analysis) and by FAME analysis (total cellular
content of the fatty acids C16 : 0 and iso-C17 : 1v10c).

Five serovars based on H-antigens and 29 phagovars using 10 phages are recognized.

Probable species synonyms -
Vibrio subtilis Ehrenberg 1835, Bacillus aterrimus
Lehmann and Neumann 1896, B. mesentericus Trevisan 1889, B. niger Migula 1900,
B. panis Migula 1900, B. vulgatus Trevisan 1889, Tyrothrix minimus Duclaux 1882,
B. nigrificans Fabian & Nienhuis 1934, B. mesentericus hydrolyticus Herman and
Neuschul 1935,
B. natto Sawamura 1906.
Bacillus subtilis
Cultural characteristics
Biochemical characters
Spores are widely distributed in nature, especially in different heat-treated materials.
The vegetative growth may occur in numerous vegetal or animal materials, inclusive
in non-acid foods. The vegetative organisms participate in the early stages of the
breakdown of organic matter. Antibiotic producer („Subtiline”).
May accumulate metal ions (aluminium, cadmium, iron and zinc) non-enzymically by
adsorption to their cell surfaces and this can be of importance in waste treatment and
natural environments.
inaquosorum was isolated from desert soil.
Is the causative agent of ropy (slimy) bread.
Bacteremia associated with immunosuppression, surgical intervention, neoplastic
disease and trauma. Other cases associated with neoplastic disease include: fatal
pneumonia and bacteremia, a septicemia and an infection of a necrotic axillary tumour in breast cancer patients; breast prosthesis
and ventriculo-atrial shunt infections; endocarditis in a drug abuser; meningitis following a head injury; cholangitis associated with
kidney and liver disease; and isolations from dermatolymphangioadenitis associated with filarial lymphedema, and from surgical
wound drainage sites.
B. subtilis has also been associated with cases of bovine mastitis and of ovine abortion. B. subtilis has been implicated in food-borne
illness: vomiting with accompanying diarrhea and the implicated foods were often prepared dishes in which meat or fish were served
with cereal-based components such as bread, pastry, rice or stuffing.
  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. 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.
  6. Rooney A.P., Price N.P.J., Ehrhardt C., Swezey J.L. and Bannan J.D., 2009. Phylogeny and molecular taxonomy of the Bacillus
    subtilis species complex and description of Bacillus subtilis subsp. inaquosorum subsp. nov. IJSEM 59, 2429-2436.
Positive results for beta-galactosidase, catalase, esculin hydrolysis, starch hydrolysis, Voges-Proskauer reaction, utilization of citrate
as a source of carbon, reduction of nitrate to nitrite & decomposition of casein, acid production from glucose, mannose, glycerol,
glycogen, salicin, D-xylose, arbutin, cellobiose, fructose, beta-gentibiose, meso-inositol, maltose, raffinose, ribose, sorbitol, sucrose,
trehalose & mannitol.

Negative results for hydrolysis of  hippurate, arginine dihydrolase, degradation of tyrosine, deamination of phenylalanine, lysine
decarboxylase, ornithine decarboxylase, acid production from adonitol, D-arabinose, D-arabitol, L-arabitol, dulcitol, erythritol,
D-fucose, L-fucose, gluconate, 2-ketogluconate, 5-ketogluconate,  lyxose, melezitose, rhamnose, sorbose, xylitol & L-xylose.

Variable results for oxidase, acid production from lactose, inulin & galactose.
(c) Costin Stoica
Culture media
Biochemical tests
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