B. atrophaeus / B. subtilis brown pigment production
|Spores and vegetative cells (malachite-green staining)
Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Bacillus, Bacillus atrophaeus Nakamura 1989.
Includes strains formerly called B. subtilis var. niger.
Probably phenotypically distinguishable from B. mojavensis, B. subtilis subsp. spizizenii and B. subtilis subsp. subtilis only by
pigment production and a negative oxidase reaction. Probably phenotypically indistinguishable from B. vallismortis.
Gram-positive, motile rods, 0.5-1.0 x 2.0-4.0 µm, central, paracentral, ellipsoidal
endospores (0.6-0.8 x 1.0-1.4µm) in unswollen sporangia.
Colonies are opaque, smooth, circular, up to 2 mm in diameter after 2 days at 28 ºC,
and form a brown-black soluble pigment in 2-6 days on media containing tyrosine or
other organic nitrogen source.
Growth is observed at pH 6 - 7; temperature range 10-55 ºC (optimum 30 ºC). NaCl is
not required for growth, 7% NaCl tolerance. Allantoin or urate are not required.
Isolated mainly from soil. No growth with lysozyme present.
Unknown. Used as bioindicator for sterilization control.
- 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,
- Nakamura L.K., 1989. Taxonomic relationship of black-pigmented Bacillus
subtilis strains and a proposal for Bacillus atrophaeus sp. nov. IJSB 39, 3, 295-
Biochemically very close to Bacillus subtilis, distinguishable only by the brown-black
pigment production (see cultural characteristics above).
Positive results for hydrolysis of gelatin, catalase, nitrate reduction, hydrolysis of
casein, hydrolysis of starch, Voges-Proskauer reaction, citrate utilization, acid
production from: L-arabinose, D-glucose, D-mannitol, salicin, fructose, sucrose,
trehalose, D- & L-xylose.
Negative results for degradation of tyrosine, arginine dihydrolase, ornithine
decarboxylase, lysine decarboxylase, deamination of phenylalanine, hydrolysis of
urea, hydrolysis of Tween 80, tryptophan deaminase, egg yolk reaction, oxidase, acid
production from: methyl beta-xyloside, beta-gentibiose, lactose & melibiose.
Variable results for acid production from: mannose, galactose, maltose, ribose &
(c) Costin Stoica