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

Abstract

Three bacterial strains, designated SSBR10-3^T, SSTM10-2^T and SSHM10-5^T, 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 SSBR10-3^T, SSTM10-2^T and SSHM10-5^T were placed within the genus Halobacillus, showing the highest similarity to Halobacillus alkaliphilus FP5^T (98.6 %), 'Halobacillus ihumii' Marseille-Q1234^T (98.5 %) and Halobacillus locisalis MSS-155^T (98.6 %), respectively. The genomic similarity values between strains SSBR10-3^T, SSTM10-2^T and SSHM10-5^T 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 SSBR10-3^T, SSTM10-2^T and SSHM10-5^T 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-C_{15 : 0}, iso-C_{16 : 0} and anteiso-C_{17 : 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 SSBR10-3^T, SSTM10-2^T and SSHM10-5^T represent novel species, for which the names Halobacillus salinarum sp. nov. (SSBR10-3^T=DSM 114353^T=KACC 21935^T=NBRC 115504^T), Halobacillus shinanisalinarum sp. nov. (SSTM10-2^T=DSM 114354^T=KACC 21936^T=NBRC 115505^T) and Halobacillus amylolyticus sp. nov. (SSHM10-5^T=DSM 114355^T= KACC 21937^T=NBRC 115506^T) are proposed.

Keywords: Halobacillus salinarum sp. nov.; Halobacillus shinanisalinarum sp. nov.; saltern; soil.