Halobacillus salinarum sp. nov., Halobacillus shinanisalinarum sp. nov. and Halobacillus amylolyticus sp. nov., isolated from saltern soil.

Abstract

Three bacterial strains, designated SSBR10-3T, SSTM10-2T and SSHM10-5T, were isolated from saltern soil sampled in Jeollanam-do, Republic of Korea. Cells were aerobic, Gram-stain-positive, flagellated and rod-shaped. The strains grew optimally at 28°C and at pH 7.0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains SSBR10-3T, SSTM10-2T and SSHM10-5T were placed within the genus Halobacillus, showing the highest similarity to Halobacillus alkaliphilus FP5T (98.6 %), 'Halobacillus ihumii' Marseille-Q1234T (98.5 %) and Halobacillus locisalis MSS-155T (98.6 %), respectively. The genomic similarity values between strains SSBR10-3T, SSTM10-2T and SSHM10-5T and their related species were 17.6-22.6 % for digital DNA-DNA hybridization (dDDH) and 69.6-78.5 % for orthologous average nucleotide identity (OrthoANI), which were lower than the thresholds recommended for species delineation. The dDDH and OrthoANI values among the three strains were below 38.3 and 89.4 %, respectively. Besides the differences in genomic features, strains SSBR10-3T, SSTM10-2T and SSHM10-5T were distinct from each other and from members of the genus in terms of phenotypic traits related to substrate assimilation. The cell-wall peptidoglycan contained meso-diaminopimelic acid, the major fatty acids were anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0, and the predominant menaquinone was MK-7 for all three strains. Diphosphatidylglycerol, phosphatidylglycerol and an unidentified phospholipid were present in their polar lipid profiles. Based on a polyphasic approach incorporating genomic data, strains SSBR10-3T, SSTM10-2T and SSHM10-5T represent novel species, for which the names Halobacillus salinarum sp. nov. (SSBR10-3T=DSM 114353T=KACC 21935T=NBRC 115504T), Halobacillus shinanisalinarum sp. nov. (SSTM10-2T=DSM 114354T=KACC 21936T=NBRC 115505T) and Halobacillus amylolyticus sp. nov. (SSHM10-5T=DSM 114355T= KACC 21937T=NBRC 115506T) are proposed.