A novel Gram-positive-staining, strictly aerobic and heterotrophic bacterium, designated strain LL-002(T), was isolated from organics- and methane-rich seafloor sediment at a depth of 100 m in Kagoshima Bay, Kagoshima, Japan. Colonies were lustreless and translucent white in colour. The temperature, pH and salt concentration ranges for growth were 10-30 degrees C, pH 6.0-6.5 and 0-1% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain LL-002(T) belongs to the genus Aneurinibacillus of the family Paenibacillaceae. 16S rRNA gene sequence similarities between strain LL-002(T) and the type strains of species of the genus Aneurinibacillus were 92.8-95.7%; the highest sequence identity was with the type strain of Aneurinibacillus migulanus. The DNA G+C content of strain LL-002(T) was 46.2 mol%. MK-7 was the predominant menaquinone. The predominant cellular fatty acids were iso-C-15:0 and anteiso-C-15 : 0, and the cell-wall peptidoglycan contained meso-diaminopimelic acid and glutamic acid, glycine and alanine in addition to muramic acid and glucosamine. The peptidoglycan type was Al gamma. In DNA DNA hybridization assays between strain LL-002(T) and the type strains of the other species of the genus Aneurinibacillus, the level of hybridization was 6.3-30.1%. On the basis of its biological features and the 16S rRNA gene sequence comparison presented here, strain LL-002(T) is considered to represent a novel species of the genus Aneurinibacillus, for which the name Aneurinibacillus tyrosinisolvens sp. nov. is proposed; the type strain is LL-002(T) (=NBRC 110097(T)=CECT 8536(T)).