A Gram-stain positive, facultative anaerobic, motile, spore-forming rod-shaped bacterium with peritrichous flagella, designated DX-5(T), was isolated from an electroactive biofilm. Growth was observed to occur at 35-60 °C, at pH 7.0-10.0 and with 0.5-10 % (w/v) NaCl (optimum growth: 50 °C, pH 8.0 and 0.5-3 % NaCl). Cells were determined to be catalase- and oxidase-positive. The predominant respiratory quinone was identified as MK-7; the major polar lipids were determined to be diphosphatidylglycerol, phosphatidylglycerol, glycolipid, aminoglycolipid and an unidentified phospholipid; the DNA G+C content was determined to be 46.6 mol%; and the major fatty acids (>5 %) were identified as anteiso-C15:0 (33.6 %), iso-C15:0 (24.1 %) and anteiso-C17:0 (13.4 %). The phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain DX-5(T) should be assigned to the genus Bacillus, and was related most closely to the type strains of B. fortis DSM 16012(T) (96.3 %), B. composti KACC 16872(T) (96.3 %) and B. fordii DSM 16014(T) (95.8 %). Results of phenotypic, chemotaxonomic and genotypic analysis indicated that strain DX-5(T) represents a novel species, for which the name B. sediminis sp. nov. is proposed. The type strain is DX-5(T) (=CGMCC 1.12412(T) = KCTC 33102(T)).