Four bacterial strains, designated K9(T), K105, K1012A and K101, were isolated from soil in Lithuania. All these strains could use n-butanol as a sole carbon source. The strains grew in a medium containing 12-120 mM n-butanol. The strains were strictly aerobic, Gram-positive endospore-formers. The best growth was achieved at 25 degrees C and pH 7.0 in medium containing 1 % (w/v) NaCl. The strains showed identical profiles of 16S-23S rRNA internal transcribed spacer PCR and nearly identical 16S rRNA gene PCR-RFLP electrophoretic patterns and physiological characteristics, demonstrating their relationship at the species level. The cellular fatty acid profile of K9(T) consisted of significant amounts of the C(15) branched-chain fatty acids iso-C(15 : 0) (16.78 %) and anteiso-C(15 : 0) (45.80 %). The diagnostic cell-wall diamino acid was meso-diaminopimelic acid. The 16S rRNA gene sequence of K9(T) showed the highest similarity to the sequences of Bacillus simplex DSM 1321(T) and Bacillus muralis LMG 20238(T) (98.3 and 97.7 %, respectively). The DNA G+C content was 37.4 mol%. Studies of DNA-DNA relatedness, morphological, physiological and chemotaxonomic analyses and phylogenetic data based on 16S rRNA gene sequencing allowed strains K9(T), K105, K1012A and K101 to be described as members of a novel species of the genus Bacillus, for which the name Bacillus butanolivorans sp. nov. is proposed. The type strain is K9(T) (=DSM 18926(T) =LMG 23974(T)).