AUTHOR=Joshi Amaraja , Thite Sonia , Karodi Prachi , Joseph Neetha , Lodha Tushar 

TITLE=Alkalihalobacterium elongatum gen. nov. sp. nov.: An Antibiotic-Producing Bacterium Isolated From Lonar Lake and Reclassification of the Genus Alkalihalobacillus Into Seven Novel Genera

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.722369

DOI=10.3389/fmicb.2021.722369

ISSN=1664-302X

ABSTRACT=<p>A Gram-stain positive, long, rod-shaped, motile, and spore-forming bacterium (MEB199<sup>T</sup>) was isolated from a sediment sample collected from Lonar Lake, India. The strain was oxidase and catalase positive. The strain grew optimally at pH 10, NaCl concentration of 3.5% at 37°C. The major fatty acids were <italic>iso-</italic>C<sub>15:0</sub>, <italic>iso-</italic>C<sub>16:0</sub>, <italic>anteiso-</italic>C<sub>15:0</sub>, and <italic>iso-</italic>C<sub>17:0</sub>. The peptidoglycan contained <italic>meso</italic>-diaminopimelic acid (<italic>meso</italic>-DAP). Phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol were the major polar lipids of MEB199<sup>T</sup>. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain MEB199<sup>T</sup> belonged to the family <italic>Bacillaceae</italic> and exhibited a distinctive position among the members of the genus <italic>Alkalihalobacillus (Ahb.)</italic>. Strain MEB199<sup>T</sup> shared the highest 16S rRNA gene sequence similarity with <italic>Alkalihalobacillus alkalinitrilicus</italic> ANL-iso4<sup>T</sup> (98.36%), whereas with type species <italic>Ahb. alcalophilus</italic> DSM 485<sup>T</sup>, it is 94.91%, indicating that strain MEB199<sup>T</sup> is distinctly related to the genus <italic>Alkalihalobacillus</italic>. The G + C content of genomic DNA was 36.47 mol%. The digital DNA–DNA hybridization (dDDH) (23.6%) and average nucleotide identity (ANI) (81%) values between strain MEB199<sup>T</sup> and <italic>Ahb. alkalinitrilicus</italic> ANL-iso4<sup>T</sup> confirmed the novelty of this new species. The pairwise identity based on the 16S rRNA gene sequence between the species of genus <italic>Alkalihalobacillus</italic> ranges from 87.4 to 99.81% indicating the heterogeneity in the genus. The different phylogenetic analysis based on the genome showed that the members of the genus <italic>Alkalihalobacillus</italic> separated into eight distinct clades. The intra-clade average amino acid identity (AAI) and percentage of conserved proteins (POCP) range from 52 to 68% and 37 to 59%, respectively, which are interspersed on the intra-genera cutoff values; therefore, we reassess the taxonomy of genus <italic>Alkalihalobacillus</italic>. The phenotypic analysis also corroborated the differentiation between these clades. Based on the phylogenetic analysis, genomic indices, and phenotypic traits, we propose the reclassification of the genus <italic>Alkalihalobacillus</italic> into seven new genera for which the names <italic>Alkalihalobacterium</italic> gen. nov., <italic>Halalkalibacterium</italic> gen. nov., <italic>Halalkalibacter</italic> gen. nov., <italic>Shouchella</italic> gen. nov., <italic>Pseudalkalibacillus</italic> gen. nov., <italic>Alkalicoccobacillus</italic> gen. nov., and <italic>Alkalihalophilus</italic> gen. nov. are proposed and provide an emended description of <italic>Alkalihalobacillus sensu stricto</italic>. Also, we propose the <italic>Ahb. okuhidensis</italic> as a heterotypic synonym of <italic>Alkalihalobacillus halodurans</italic>. Based on the polyphasic taxonomic analysis, strain MEB199<sup>T</sup> represents a novel species of newly proposed genus for which the name <italic>Alkalihalobacterium elongatum</italic> gen. nov. sp. nov. is proposed. The type strain is MEB199<sup>T</sup> (= MCC 2982<sup>T</sup>, = JCM 33704<sup>T</sup>, = NBRC 114256<sup>T</sup>, = CGMCC 1.17254<sup>T</sup>).</p>