Thirty strains were isolated from pasteurized soil samples by enrichment culture in aerobiosis at 32 degrees C in a minimal medium containing one of the following compounds as sole source of carbon and energy: quinate, p-hydroxybenzoate, phthalate, isophthalate or trimellitate. These bacteria were rods (0.8 X 2-7 micron), motile by peritrichous flagella. Endospores were oval (1.4-1.8 X 2 micron) and distinctly swelled the sporangia. The Gram reaction was variable but the Gram type was positive. Colonies were smaller on peptone (0.4%) agar than on minimal salts-glucose (0.2%) agar. The following characters were always present: growth in the presence of lysozyme, cytochrome c oxidase, catalase, nitrate assimilation, urease, amylase and L-glutamate dehydrogenase. The cells contained glycogen. In anaerobiosis, glucose was not fermented and nitrate was not used as a respiratory acceptor of electrons. Of 215 substrates tested, 31 (including 9 aromatic compounds) were used as sole carbon and energy sources by all 30 strains, and 38 substrates (including 13 aromatic compounds) were used by only some of them; 146 substrates (including 49 aromatic compounds) were not used by any of the 30 strains. No amino acid could be used as sole carbon and energy source. Numerical analysis of the 30 strains showed an aggregate cluster made of 5 phena. The mean G + C content of the DNA was 55 +/- 0.6 mol %. The described bacteria are clearly different from the 2 known species of the second morphological group which cannot ferment carbohydrates: Bacillus brevis and B. azotoformans. Strain Q1 (ATCC 29948) is the holotype of Bacillus gordonae sp. nov.