A polyphasic taxonomic study was conducted on two Gram-negative, non-sporulating, non-motile bacterial strains, S2-20-2T and S2-21-1, isolated from a contaminated freshwater sediment in China. Comparative 16S rRNA gene sequence studies revealed a clear affiliation of two strains with Bacteroidetes, which showed the highest pairwise sequence similarities with Hymenobacter duratus BT646T (99.3%), Hymenobacter psychrotolerans Tibet-IIU11T (99.3%), Hymenobacter kanuolensis T-3T (97.6%), Hymenobacter swuensis DY53T (96.9%), Hymenobacter tenuis POB6T (96.8%), Hymenobacter seoulensis 16F7GT (96.7%), and Hymenobacter rigui KCTC 12533T (96.5%). The phylogenetic analysis based on 16S rRNA gene sequences showed that two strains formed a clear phylogenetic lineage with the genus Hymenobacter. Major fatty acids were identified as iso-C15:0, anteiso-C15:0, and summed feature 3 (C16:1 ω6c and/or C16:1 ω7c/t) and summed feature 4 (iso-C17:1 I and/or anteiso-C17:1 B). Major cellular polar lipids were identified as phosphatidylethanolamine, three unidentified aminolipids, an unidentified aminophosopholipid and an unidentified lipid. The respiratory quinone was detected as MK-7 and the genomic DNA G + C content was determined to be 57.9% (genome) for type strain S2-20-2T and 57.7 mol% (HPLC) for strain S2-21-1. The observed ANI and dDDH values between strain S2-20-2T and its closely related strains were 75.7-91.4% and 21.2-43.9%, respectively. Based on physiological, biochemical, genetic and genomic characteristics, we propose that strains S2-20-2T and S2-21-1 represent a novel species of the genus Hymenobacter, for which the name Hymenobacter sediminicola sp. nov. is proposed. The type strain is S2-20-2T (= CGMCC 1.18734T = JCM 35801T).
Keywords: Hymenobacter; Hymenobacter sediminicola; S2-20-2; S2-21-1.
© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.