FAMILY I. BACILLACEAE
72
List of species of the genus Bacillus*
1. Bacillus subtilis (Ehrenberg 1835) Cohn 1872, 174AL Nom.
cons. Nomencl. Comm. Intern. Soc. Microbiol. 1937, 28;
Opin. A. Jud. Comm. 1955, 39 (Vibrio subtilis Ehrenberg
1835, 279.)
sub¢ti.lis. L. adj. subtilis slender.
Aerobic, Gram-positive, motile rods, forming ellipsoidal to cylindrical spores which lie centrally, paracentrally
and subterminally in unswollen sporangia (Figure 10g).
Cells grown on glucose agar stain evenly. Cells 0.7–0.8 by
2.0–3.0 µm, occurring singly and in pairs, seldom in chains.
Colonial morphology is exceptionally variable, within and
between strains, and may give the appearance of a mixed
culture. Colonies are round to irregular in shape and of
moderate (2–4 mm) diameter, with margins varying from
undulate to fimbriate; they become opaque, with surfaces
that are dull and which may become wrinkled; color is whitish, and may become creamy or brown; textures range from
moist and butyrous or mucoid, through membranous with
an underlying mucoid matrix, with or without mucoid beading at the surface, to rough and crusty as they dry (Figure
9g). 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 “Bacillus subtilis
var. aterrimus.” Strains forming brownish-black pigment on
tyrosine (and so often evident on the crude media available
to earlier workers), and often formerly called “Bacillus subtilis var. niger,” have been split from Bacillus subtilis as Bacillus
atrophaeus.
Optimum growth temperature 28–30 °C, with minimum of 5–20 °C and maximum of 45–55 °C. Growth occurs
between pH 5.5 and 8.5, but limits have not been recorded.
Some restricted anaerobic growth may occur in complex
media with glucose or (less effectively) nitrate. Growth
occurs on minimal medium with glucose and an ammonium
salt as sole sources of carbon and nitrogen. Grows in presence of up to 7% NaCl, some strains will tolerate 10% NaCl.
Catalase-positive, oxidase variable. Casein, esculin, gelatin
and starch are hydrolyzed, phenylalanine and urea are not
hydrolyzed. Pectin and polysaccharides of plant tissues are
decomposed. Dextran and levan are formed extracellularly
from sucrose. Citrate is utilized as sole carbon source by
most strains; propionate is not utilized. Nitrate is reduced
to nitrite. Voges–Proskauer-positive. Acid without gas is produced from glucose and from a wide range of other carbohydrates.
The practical values of the distinction of the subspecies
of Bacillus subtilis and of the species Bacillus mojavensis and
Bacillus vallismortis are questionable. The distinction of
*
Type strains distributed by international culture collections may be subjected to
quality control, and the user should establish whether or not this is the case.
The type strain accession numbers shown for Bacillus species were chosen to give
an acceptable geographic spread. Sometimes more than one 16S rRNA gene
sequence is available from EMBL/GenBank for different subcultures of the same
type strain; we indicate alongside the EMBL/GenBank accession number which
sequence has been used to construct the tree (Figure 8). Other sequences may or
may not be reliable and users of these should check carefully.
Bacillus atrophaeus from the Bacillus subtilis subspecies and
from Bacillus mojavensis and Bacillus vallismortis is dependent
upon brownish-black pigment production on tyrosine agar
by strains of Bacillus atrophaeus. See Table 5.
Endospores are very widespread in soil, dust and on vegetation, and in many other environments. The vegetative
organisms participate in the early stages of the breakdown
of organic matter. Causative agent of ropy (slimy) bread.
1a. Bacillus subtilis subsp. subtilis Nakamura, Roberts and Cohan 1999, 1214VP
Description is that given above for the species.
Phenotypically similar to Bacillus atrophaeus and distinguishable from that species only by the pigmentation of the
latter. Not distinguishable from Bacillus mojavensis, Bacillus
subtilis subsp. spizizenii and Bacillus vallismortis by conventional phenotypic tests.
DNA G + C content (mol%): 41.5–47.5 (Tm) for 31 strains,
41.8–46.3 (Bd) for 34 strains, and 42.9 (Tm) for the type strain.
Type strain: ATCC 6051, IAM 12118, CCM 2216, DSM 10,
IFO 12210, NCIMB 3610, NCTC 3610, NRRL NRS-744.
EMBL/GenBank accession (16S rRNA gene): AB042061
(IAM 12118).
Additional remarks: Strains designated by Gibson (1944)
and Smith et al. (1946) as synonyms of Bacillus subtilis
included Bacillus aterrimus, Bacillus mesentericus, Bacillus
natto, Bacillus niger, Bacillus nigrificans and Bacillus panis.
“Bacillus natto” is a name given to Bacillus subtilis strains
associated with natto, a Japanese food made by fermenting soybeans with these organisms. Strains formerly designated “Bacillus amyloliquefaciens” or “Bacillus subtilis var.
amyloliquefaciens” are now accommodated within Bacillus
amyloliquefaciens.
1b. Bacillus subtilis subsp. spizizenii Nakamura, Roberts and
Cohan 1999, 1214VL
spi.zi.ze¢ni.i. L. gen. n. spizizenii named after the American
bacteriologist J. Spizizen.
Phenotypically indistinguishable from Bacillus subtilis
subsp. subtilis, and separated from that taxon only by DNA
relatedness values of 58–68% with 12 strains of that subspecies, by the presence of ribitol in the cell wall, and by transformation studies.
The type strain was isolated from Tunisian soil.
Type strain: NRRL B-23049, DSM 15029, LMG 19156,
KCTC 3705.
EMBL/GenBank accession number (16S rRNA gene):
AF074970 (NRRL B-23049).
2. Bacillus aeolius Gugliandolo, Maugeri, Caccamo and Stackebrandt 2003b, 1701VP (Effective publication: Gugliandolo,
Maugeri, Caccamo and Stackebrandt 2003a, 175.)
ae.o¢li.us. L. adj. aeolius pertaining to the Eolian Island
(Insulae Aeoliae) where the organism was isolated from a
shallow marine hydrothermal vent.
Aerobic, Gram-positive, motile rods, 0.5 µm by 2.0 µm,
forming terminal, oval endospores. Description is based upon
a single isolate. Catalase-negative, oxidase-positive. Growth
GENUS I. BACILLUS
73
TABLE 3. Differential characteristics of the species of the genus Bacillusa,b
(continued)
GENUS I. BACILLUS
89
TABLE 4. (continued)
a
Symbols: +, >85% positive; d, variable (16–84% positive); −, 0–15% positive; w, weak reaction; d/w, variable and weak when positive; no
entry indicates that no data are available.
b
Compiled from Larkin and Stokes (1967); Nakayama and Yanoshi (1967); Gordon et al. (1973), Pichinoty et al. (1984, 1976, 1983);
Aragno (1978); Schenk and Aragno (1979); Pichinoty (1983); Bonjour and Aragno (1984); Logan and Berkeley (1984); Claus and Berkeley
(1986); Priest et al. (1987, 1988); Nakamura et al. (1988, 1999, 2002) Demharter and Hensel (1989b)<qu ref=81>; Denariaz et al. (1989);
Nakamura (1989, 1998); Ventosa et al. (1989); Tomimura et al. (1990); Nagel and Andreesen (1991); Arfman et al. (1992); Spanka and
Fritze (1993); Andersch et al. (1994); Roberts et al. (1994, 1996); Agnew et al. (1995); Boone et al. (1995); Combet-Blanc et al. (1995);
Nielsen et al. (1995a); Fritze (1996a); Fujita et al. (1996); Kuhnigk et al. (1995); Kuroshima et al. (1996); Pettersson et al. (2000, 1996);
Shelobolina et al. (1997); Lechner et al. (1998); Switzer Blum et al. (1998); Yumoto et al. (1998, 2003, 2004c); Rheims et al. (1999); Logan
et al. (2002a, b, 2000, 2004b); Palmisano et al. (2001); Yoon et al. (2001a); Abd El-Rahman et al. (2002); Ajithkumar et al. (2002); Kanso
et al. (2002); Li et al. (2002); Reva et al. (2002); Venkateswaran et al. (2003); Gugliandolo et al. (2003a); Heyrman et al. (2003a, 2005a,
2004); Taubel et al. (2003); Yoon et al. (2003a); De Clerck et al. (2004b, 2004c); Heyndrickx et al. (2004); La Duc et al. (2004); Ivanova et
al. (2004a); Noguchi et al. (2004); Santini et al. (2004); Scheldeman et al. (2004); Suresh et al. (2004).
c
Reactions differ between strains of the emetic biotype of Bacillus cereus for these substrates.
d
Results obtained when inocula are supplemented with 7% NaCl.
e
Results obtained when grown at pH 10.
f
Assimilation data for Bacillus simplex are for the type strain only.
6. B. amyloliquefaciens
11. B. atrophaeus
51. B. licheniformis
57. B. mojavensis
73. B. pumilus
83. B. sonorensis
91. B. vallismortis
Characteristic
1. B. subtilis subspp.
subtilis and spizizeniic
TABLE 5. Differentiation of Bacillus subtilis from closely related Bacillus speciesa,b
−d
−d
−
−
−
−
−
+f
−
−
−
+
−
−
−
−
−
−
we
−
+
−
−
−
+
−
+
+
−
+
+
−
+
+
−
+
nd
nd
nd
+
−
+
+
−
+
+
+
+
nd
nd
nd
+
−
+
−
+
−
−
−
−
nd
nd
nd
+
+
+
nd
nd
nd
+
−
+
+
+
nd
+
nd
d
+
+
nd
+
+
nd
+
+
+
+
+
+
−
−
−
+
+
+
−
d
d
−
−
−
−
+
−
−
d
+
+
d
−
−
−
+
d
−
d
+
+
d
−
d
d
d
−
−
−
−
+
+
−
d
+
+
−
−
Pigmented colonies
Yellow-pink-red
Dark brown/black
Anaerobic growth
Acid from:
Glycogen
Methyl α-d-mannoside
Starch
Hydrolysis of starch
Utilization of propionate
Nitrate reduction
Growth in NaCl:
5%
7%
10%
Growth at:
5 °C
10 °C
50 °C
55 °C
65 °C
a
Symbols: +, >85% positive; d, different strains give different reactions (16–84% positive); −, 0–15% positive; w, weak reaction; nd, no data are available.
b
Compiled from Claus and Berkeley (1986), Priest et al. (1987), Nakamura (1989), Roberts et al. (1994,
1996), Nakamura et al. (1999), and Palmisano et al. (2001).
c
The subspecies of Bacillus subtilis are not distinguishable by routine phenotypic tests.
d
Bacillus subtilis may form pigments, varying from cream through yellow, orange, pink and red, to brown
or black, on potato or agar media containing glucose; strains forming brown or black pigment were often
formerly called “Bacillus subtilis var. aterrimus.”
e
Colonies are yellowish-cream on routine media, and bright yellow on pH 5.6 agar.
f
This species accommodates strains forming brownish-black pigment on tyrosine (and so often evident on
the crude media available to earlier workers), and often formerly called “Bacillus subtilis var. niger.”