Deinococcus knuensis sp. nov., a bacterium isolated from river water

Area of Science:

• Microbiology
• Bacteriology
• Environmental Science

Background:

• The genus Deinococcus comprises extremophilic bacteria known for their radiation resistance.
• River water environments are diverse microbial habitats.
• Characterization of novel bacterial species is crucial for understanding microbial diversity and adaptation.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from river water.
• To determine the taxonomic position of the novel strain using polyphasic methods.
• To propose a new species within the Deinococcus genus.

Main Methods:

• Isolation of bacteria from Han River water.
• Physicochemical characterization including growth conditions (temperature, pH, NaCl tolerance).
• Molecular phylogenetic analysis (16S rRNA gene sequencing) and DNA-DNA hybridization.
• Chemotaxonomic analysis (respiratory quinones, polar lipids, fatty acids) and DNA G+C content determination.

Main Results:

• A novel Gram-negative, aerobic, non-motile bacterium, strain 16F3H^T, was isolated.
• The strain exhibits tolerance to a wide range of temperatures (10-42°C), pH (4-10), and NaCl concentrations (up to 4%).
• Phylogenetic analysis showed close relatedness to 'Deinococcus seoulensis', with DNA-DNA hybridization values confirming its novelty. Chemotaxonomic data and DNA G+C content (65.7 mol%) were consistent with the genus Deinococcus.

Conclusions:

• Strain 16F3H^T represents a novel species within the genus Deinococcus.
• The proposed name for this new species is Deinococcus knuensis sp. nov.
• This finding contributes to the understanding of microbial diversity in freshwater ecosystems and the adaptive capabilities of Deinococcus species.