Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Bacillus, Bacillus firmus Werner (1933).
Possible synonym: Bacillus imomarinus ZoBell and Upham 1944. Differentiated in two biovars by some sugars fementation and
substrates utilization as sole carbon source.
Gram-positive, 1.2-3.8 / 0.6-1.0 µm, motile by peritrichous flagella.
Spores are oval or cylindrical, subterminal, paracentral or central, rarely swelling the
On TSA at 30 ºC, after 3 days, colonies are 1-12 mm in diameter, creamy-yellow to
pale orange-brown , with margins that vary from entire to finely rhizoidal, and surface
appearances that are egg-shell to glossy, sometimes with granular or zoned areas in
Facultatively anaerobic. Maximum temperature 40 - 50 ºC; minimum temperature,
5-20 ºC, optimum 20-30 ºC. Grows in 2-7% NaCl. Optimum pH 7-9 (growth range
6-11). NaCl, allantoin or urate are not required for growth.
Sparsely represented in nature, has been isolated mainly from soil.
- Gordon R.E., Haynes W.C., Pang C.H. (1973) – The genus Bacillus . Agriculture Handbook No. 427, U.S.D.A., Washington D.C.
- 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.
- Buiuc D., Negut M. , 2009. Tratat de Microbiologie Clinica, editia a III-a, Bucuresti.
- 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, starch hydrolysis, reduction of nitrate to nitrite, decomposition of casein (weak), gelatin liquefaction, acid
from: glucose, mannitol, glycerol, starch, N-acetyl-D-glucosamine, maltose, sucrose & trehalose.
Negative results for Voges-Proskauer test, resistance to lysozyme, utilization of citrate and propionate, indole production, arginine
dihydrolase, lysine decarboxylase, ornithine decarboxylase, H2S production, tryptophan deaminase, beta-galactosidase, hydrolysis of
urea, egg yolk reaction, acid production from: L-xylose, methyl beta-xyloside, salicin, D- or L-arabinose, D-mannose, adonitol,
amygdalin, D- or L-arabitol, arbutin, cellobiose, dulcitol, erythritol, D- or L-fucose, galactose, beta-gentibiose, gluconate,
meso-inositol, inulin, 2- or 5-ketogluconate, lactose, lyxose, melezitose, melibiose, raffinose, rhamnose, ribose, sorbitol, sorbose &
Variable results for esculin hydrolysis, acid from D-xylose, glycogen, fructose
(c) Costin Stoica