Two Gram-stain-negative, facultative anaerobic and non-motile bacteria, strains R11T and S1162T, were isolated from soil in the Republic of Korea. Both strains were catalase- and oxidase-positive and contained menaquinone-7 as the major isoprenoid quinone. Strain R11T contained summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C15:0, C16:0 and iso-C17:0 3-OH as major fatty acids and phosphatidylethanolamine, an unidentified aminophospholipid and an unidentified aminolipid as major polar lipids; while strain S1162T contained summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C15:0, iso-C17:0 3-OH, C16:0 and summed feature 9 (10-methyl C16:0 and/or iso-C17:1 ω9c) as major fatty acids and phosphatidylethanolamine and an unidentified aminophospholipid as major polar lipids. The DNA G+C contents of strains R11T and S1162T calculated from their whole genomes were 42.7 and 42.9 mol%, respectively. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain R11T formed a phylogenetic lineage with Mucilaginibacter jinjuensis YC7004T and strain S1162T formed a distinct phyletic lineage from closely related type strains within the genus Mucilaginibacter. Strains R11T and S1162T were most closely related to M. jinjuensis YC7004T and Mucilaginibacter panaciglaebae BXN5-31T with 97.78 and 97.23% 16S rRNA gene sequence similarities, respectively. On the basis of phenotypic, chemotaxonomic and molecular analysis, strains R11T and S1162T represent two novel species of the genus Mucilaginibacter, for which the names Mucilaginibacter agri sp. nov. and Mucilaginibacter humi sp. nov. are proposed, respectively. The type strains of M. agri and M. humi are R11T (=KACC 21228T=JCM 33472T) and S1162T (=KACC 21669T=JCM 33916T), respectively.
Keywords: Mucilaginibacter agri; Mucilaginobacter humi; bacteroidetes; new taxa; soil.