Flavobacterium fluvii sp. nov., isolated from stream sediment

Area of Science:

• Microbiology
• Bacteriology
• Taxonomy

Background:

• The genus Flavobacterium comprises diverse Gram-negative bacteria, often found in various environmental niches.
• Accurate taxonomic classification is crucial for understanding microbial ecology and function.

Purpose of the Study:

• To characterize and classify a novel bacterium isolated from a South Korean stream.
• To determine the phylogenetic position and taxonomic status of the novel isolate within the genus Flavobacterium.

Main Methods:

• Isolation and cultivation of aerobic, yellow-pigmented bacteria from stream sediment.
• Phenotypic characterization including cell morphology, pigment production, and enzymatic activities.
• Physicochemical analyses including fatty acid composition, isoprenoid quinones, and DNA G+C content.
• Molecular phylogenetic analyses using 16S rRNA gene sequencing and DNA-DNA hybridization.

Main Results:

• Strain H7(T) was identified as a non-motile, Gram-negative, yellow-pigmented rod producing flexirubin pigments.
• Key chemotaxonomic features included iso-C15:0, anteiso-C15:0 as major fatty acids and menaquinone-6 (MK-6) as the predominant isoprenoid quinone.
• Phylogenetic analysis based on 16S rRNA gene sequences placed strain H7(T) within the genus Flavobacterium, closely related to F. limicola and F. resistens.
• Low DNA-DNA relatedness values (18% and 14%) with closely related species confirmed its status as a distinct species.

Conclusions:

• Strain H7(T) represents a novel species within the genus Flavobacterium.
• The proposed name for this novel species is Flavobacterium fluvii sp. nov.
• The type strain is H7(T) (=KACC 12818(T)=DSM 19978(T)).