Bacillus eiseniae sp. nov., a swarming, moderately halotolerant bacterium isolated from the intestinal tract of an earthworm (Eisenia fetida L.)

Abstract

A swarming and moderately halotolerant bacterium, designated strain A1-2(T), was isolated from the intestinal tract of the earthworm Eisenia fetida L. Cells were endospore-forming rods that were facultatively anaerobic, catalase-positive, oxidase-negative and motile by peritrichous flagella. The isolate grew optimally at 30 °C and pH 7.0, and could grow with up to 9 % (w/v) NaCl. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain A1-2(T) belonged to the genus Bacillus and exhibited 16S rRNA gene sequence similarities of 96.8, 96.0, 96.0, 96.4 and 96.7 % with Bacillus drentensis LMG 21831(T), B. horneckiae PT-45(T), B. niacini BAC 1015, B. infantis SMC 4352-1(T) and B. shackletonii LMG 18435(T), respectively. DNA-DNA relatedness values between the isolate and the reference strains were ≤ 38.3 %. The DNA G+C content of strain A1-2(T) was 38.5 mol%. The predominant menaquinone was MK-7 and the major polar lipids were diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were iso-C(15 : 0) (51.5 %) and anteiso-C(15 : 0) (29.6 %) and the cell-wall diamino acid was meso-diaminopimelic acid. On the basis of 16S rRNA gene sequence analysis and chemotaxonomic and phenotypic characteristics, it is concluded that strain A1-2(T) represents a novel species of the genus Bacillus, for which we propose the name Bacillus eiseniae sp. nov. The type strain is A1-2(T) (= KCCM 90092(T) = JCM 16993(T)).