Bacillus alveayuensis sp. nov., a thermophilic bacterium isolated from deep-sea sediments of the Ayu Trough

Abstract

Two thermophilic, spore-forming strains, TM1Tand TM5, were isolated from deep-sea sediment (4000 m below sea level) of the Ayu Trough in the western Pacific Ocean. Cells of the two strains were Gram-positive, motile and rod-shaped. Their spores were ellipsoidal, subterminal to terminal and occurred in swollen sporangia. The two strains grew at temperatures up to 65 °C and in the pH range 6·5–9·0. The NaCl concentration for optimal growth was 3·0 % (w/v) and growth was inhibited by 5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains TM1Tand TM5 belonged to the genusBacillus, and that strain TM1Twas most closely related toBacillus aeoliusDSM 15084T(96·7 %),Bacillus smithiiDSM 4216T(96·1 %),Bacillus methanolicusNCIMB 13113T(95·8 %) andBacillus pallidusDSM 3670T(95·7 %). Between the 16S rRNA gene sequences of strains TM1Tand TM5 there were only three nucleotide differences, implying that the two strains were of the same species. The cellular fatty acid profiles of the two strains were also very similar, with iso-C15 : 0, iso-C16 : 0, C16 : 0, iso-C17 : 0and anteiso-C17 : 0as the major components. The G+C content of strain TM1Twas 38·7 %. On the basis of phenotypic and molecular data, strains TM1Tand TM5 represent a novel species of the genusBacillus, for which the nameBacillus alveayuensissp. nov. is proposed. The type strain is TM1T(=KCTC 10634T=JCM 12523T).