Anoxybacillus geothermalis sp nov., a facultatively anaerobic, endospore-forming bacterium isolated from mineral deposits in a geothermal station

A novel endospore-forming bacterium designated strain GSsed3(T) was isolated from deposits clogging aboveground filters from the geothermal power platform of Gross Schonebeck in northern Germany. The novel isolate was Gram-staining-positive, facultatively anaerobic, catalase-positive and oxidase-positive. Optimum growth occurred at 60 degrees C, 0.5% (w/v) NaCl and pH 7-8. Analysis of the 16S rRNA gene sequence similarity indicated that strain GSsed3(T) belonged to the genus Anoxybacillus, and showed 99.8% sequence similarity to Anoxybacillus rupiensis R270(T), 98.2% similarity to Anoxybacillus tepidamans GS5-97(T), 97.9% similarity to Anoxybacillus voinovskiensis TH13(T), 97.7% similarity to Anoxybacillus caldiproteolyticus DSM 15730(T) and 97.6% similarity to Anoxybacillus amylolyticus MR3C(T). DNA-DNA hybridization (DDH) indicated only 16% relatedness to Anoxybacillus rupiensis DSM 17127(T). Furthermore, DDH estimation based on genomes analysis indicated only 19.9% overall nucleotide similarity to Anoxybacillus amylolyticus DSM 15939(T). The major respiratory menaquinone was MK-8. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unknown phosphoglycolipid and one unknown phospholipid. The predominant cellular fatty acids were iso-C-15:0, iso-C-17:0, C-16:0, iso-C-16:0 and anteiso-C-17:0. The peptidoglycan type was A1g meso-Dpm-direct. The genomic DNA G+C content of the strain was 46.9 mol%. The phenotypic, genotypic and chemotaxonomic characterization indicated that strain GSsed3(T) differs from related species of the genus. Therefore, strain GSsed3(T) is considered to be a representative of a novel species of the genus Anoxybacillus, for which the name Anoxybacillus geothermalis sp. nov. is proposed. The type strain of Anoxybacillus geothermalis is GSsed3(T) (= CCOS808(T) = ATCC BAA2555(T)).