Hymenobacter knuensis sp. nov., Isolated From River Water

Area of Science:

• Microbiology
• Bacteriology
• Taxonomy

Background:

• The genus Hymenobacter, belonging to the Cytophagaceae family within the phylum Bacteroidetes, comprises aerobic, Gram-negative bacteria.
• Members of this genus are often isolated from diverse environmental sources, including soil and water.

Purpose of the Study:

• To taxonomically characterize a novel bacterial isolate, strain 16F7C-2^T, obtained from the Han River, South Korea.
• To determine the phylogenetic and genotypic relationship of the isolate to known Hymenobacter species.

Main Methods:

• Polyphasic taxonomic approach including 16S rRNA gene sequence analysis.
• Determination of DNA G+C content, respiratory quinone, fatty acid profiles, and polar lipid composition.
• DNA-DNA hybridization experiments to assess genomic relatedness.

Main Results:

• Strain 16F7C-2^T showed highest 16S rRNA gene sequence similarity to Hymenobacter algoricola (98.3%) and Hymenobacter fastidiosus (97.7%).
• Chemotaxonomic analyses, including menaquinone, fatty acid, and polar lipid profiles, supported affiliation with the genus Hymenobacter.
• DNA-DNA relatedness values of 45.2% with H. algoricola and 40.3% with H. fastidiosus indicated that the isolate represents a new genospecies.

Conclusions:

• Strain 16F7C-2^T could be clearly differentiated from its closest Hymenobacter relatives based on phenotypic, genotypic, and chemotaxonomic characteristics.
• The novel isolate constitutes a new species within the genus Hymenobacter.
• The proposed name for the novel species is Hymenobacter knuensis sp. nov., with strain 16F7C-2^T as the type strain.