Hymenobacter cheonanensis sp. nov., and Hymenobacter convexus sp. nov. isolated from the construction site

Two aerobic bacterial isolates, designated as strains CA2-7^T and CA1UV-4^T, were isolated from soil samples collected at a construction site in Cheonan. Both strains were identified as Gram-stain-negative, rod-shaped and a phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains constitute a distinct lineage within the family Hymenobacter (order Cytophagales, class Cytophagia). The closest genetic relatives were found to be members of the genus Hymenobacter, specifically Hymenobacter ginkgonis HMF4947^T (with 16S rRNA gene sequence similarity of 97.28%) and Hymenobacter segetis S7-3-11^T (98.10%). Both strains grew optimally at pH 7.0, 25 °C, without NaCl. Fatty acid analysis revealed distinctive profiles, with C_15:0 anteiso and C_15:0 iso predominating in strain CA2-7^T, while C_15:0 iso and summed feature 3 (C_16:1 ω7c/C_16:1 ω6c) were the primary fatty acids in strain CA1UV-4^T. Both strains exhibited MK-7 as the major respiratory quinone. Biochemical, chemotaxonomic, and phylogenetic data support CA2-7^T and CA1UV-4^T as new Hymenobacter species. Accordingly, we suggest the names Hymenobacter cheonanensis and Hymenobacter convexus for strains CA2-7^T (= KCTC 92968^T = NBRC 116577^T) and CA1UV-4^T (= KCTC 92970^T = NBRC 116576^T), respectively.