A novel long-chain, Gram-positive, rod-shaped, endospore-forming strain was isolated from the influent of a drinking water treatment plant in Macau, China. This facultatively anaerobic isolate (2.0-5.0 microm in length and 0.8-1.2 microm in diameter) formed long chains over 100 microm in length in both liquid and solid media. It had a growth temperature range of 20-40 degrees C, with an optimum at about 30 degrees C, and a growth pH range of 6.0-10.0, with an optimum at pH 8.5. The G+C content of the DNA extracted was 40.8 mol%. The main fatty acid components were anteiso-C(15:0) (67.2%) and iso-C(15:0) (21.7%), with small quantities of iso-C(14:0), C(14:0), iso-C(16:0) and iso-C(17:0). The main quinone component was MK-7. Phylogenetic analyses based on its 16S rRNA gene sequence revealed that this isolate is a member of the genus Bacillus, with no close relatives at the species level (sequence similarity <96.1%). These phenotypic and genetic properties suggested that this strain represents a novel species, for which the name Bacillus macauensis sp. nov. is proposed. The type strain is ZFHKF-1T (=JCM 13285T=DSM 17262T).