Janibacter zhaoxuefangae sp. nov. and Janibacter zhangyanbonis sp. nov., two novel Actinobacteria isolated from in situ coal

Four novel bacterial strains, designated as G56^T, G1551, G349^T and G368, were isolated from <i>in situ</i> coal samples. All four strains were Gram-stain-positive, catalase-positive, oxidase-negative, non-motile and aerobic. Phylogenetic analysis based on 16S rRNA gene sequences revealed that G56^T and G1551 represented the same species, and that G349^T and G368 represented another species, with both species falling within the genus <i>Janibacter</i>. Strains G56^T and G1551 exhibited the highest 16S rRNA gene sequence similarity to <i>Janibacter anophelis</i> CCUG 49715^T (98.61%), whereas strains G349^T and G368 exhibited the highest 16S rRNA gene sequence similarity to <i>Janibacter limosus</i> DSM 11140^T and <i>Janibacter terrae</i> NBRC 107853^T (99.03-99.10%). The average nucleotide identity and digital DNA-DNA hybridization values between the proposed type strains (G56^T and G349^T) and species of the genus <i>Janibacter</i> were 74.59-89.54% and 19.70-38.30%, respectively. The DNA G+C contents of G56^T and G349^T were 71.0 and 71.5 mol%, respectively, and both strains contained only menaquinone MK-8(H₄) as the respiratory quinone. The major cellular fatty acids of strain G56^T were C_16:0 10-methyl and/or iso-C_17:1 <i> ω</i>9<i>c</i>, iso-C_17:0 and iso-C_15:0, whereas those of strain G349^T were C_18:1 <i> ω</i>9<i>c</i>, iso-C_16:0 and C_17:1 <i> ω</i>8<i>c</i>. The polar lipid profiles of both strains comprised diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol, and <i>meso</i>-diaminopimelic acid was identified as the diagnostic diamino acid in the cell wall. Based on phenotypic, phylogenetic and chemotaxonomic evidence, strains G56^T and G349^T were considered to represent two novel species of the genus <i>Janibacter</i>, for which the names <i>Janibacter zhaoxuefangae</i> sp. nov. and <i>Janibacter zhangyanbonis</i> sp. nov. are proposed. The type strains are G56^T (=GDMCC 1.5581^T=JCM 37886^T) and G349^T (=GDMCC 1.5549^T=JCM 37887^T).