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 in situ 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 Janibacter. Strains G56^T and G1551 exhibited the highest 16S rRNA gene sequence similarity to Janibacter anophelis CCUG 49715^T (98.61%), whereas strains G349^T and G368 exhibited the highest 16S rRNA gene sequence similarity to Janibacter limosus DSM 11140^T and Janibacter terrae 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 Janibacter 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 ω9c, iso-C_17:0 and iso-C_15:0, whereas those of strain G349^T were C_18:1 ω9c, iso-C_16:0 and C_17:1 ω8c. The polar lipid profiles of both strains comprised diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol, and meso-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 Janibacter, for which the names Janibacter zhaoxuefangae sp. nov. and Janibacter zhangyanbonis 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).