Bacillus solimangrovi sp. nov., isolated from mangrove soil

Abstract

Two novel bacterial strains, GH2-4T and GH2-5, were isolated from mangrove soil near the seashore of Weno island in Chuuk state, Micronesia, and were characterized by a polyphasic approach. The two strains were strictly aerobic, Gram-staining-positive, motile, endospore-forming rods that were catalase- and oxidase-positive. Colonies were circular, convex, stringy and transparent yellowish (GH2-4T) or opaque whitish (GH2-5). The 16S rRNA gene sequences of the two isolates were identical. The most closely related strains in terms of 16S rRNA gene sequence similarity were Bacillus kochii WCC 4582T, B. horneckiae DSM 23495T, B. azotoformans LMG 9581T, B. cohnii DSM 6307T and B. halmapalus DSM 8723T (95.6, 95.4, 95.4, 95.2 and 95.2% similarity, respectively). The partial groEL sequence of strain GH2-4T was identical to that of strain GH2-5 and showed <85% similarity to those of the most closely related strains. The isolates grew at pH 5-12 (optimal growth at pH 9), at 10-40 °C (optimum 30-35 °C) and at 0-9% (w/v) NaCl (optimum 1-3% NaCl). The cell-wall peptidoglycan of strains GH2-4T and GH2-5 contained meso-diaminopimelic acid and cell-wall hydrolysates contained ribose as a major sugar. The DNA G+C content was 36 mol%, and DNA-DNA relatedness between the isolates and five related reference strains was 20-24%. Strain GH2-4T exhibited 81% DNA-DNA relatedness with strain GH2-5. The major cellular fatty acids of both strains were iso-C15:0, iso-C16:0, iso-C14:0 and anteiso-C15:0 and the predominant menaquinone was MK-7. On the basis of the evidence from this polyphasic study, strains GH2-4T and GH2-5 (=KCTC 33143=JCM 18995=DSM 27084) represent a novel species of the genus Bacillus, for which the name Bacillus solimangrovi sp. nov. is proposed; the type strain is GH2-4T (=KCTC 33142T=JCM 18994T=DSM 27083T).