Tenacibaculum skagerrakense sp. nov., a marine bacterium isolated from the pelagic zone in Skagerrak, Denmark

This study describes the isolation and characterization of two bacterial strains (D28 and D30T) from pelagic seawater at 30 meters depth in Skagerrak, Denmark. Using 16S rRNA gene sequencing, DNA-DNA hybridization, and phenotypic analysis, the researchers determined that these Gram-negative, oxidase- and catalase-positive bacteria belong to a novel species within the genus Tenacibaculum, a member of the Flavobacteriaceae family. The strains were designated Tenacibaculum skagerrakense sp. nov., with D30T as the type strain. Unlike previously described Tenacibaculum species isolated from marine organism surfaces, these strains appear to be free-living pelagic bacteria. They exhibit distinctive characteristics including bright yellow colonies, growth at temperatures between 10-40°C (optimal 25-37°C), requirement for sea salts (1/4 to 150% strength seawater), and the ability to hydrolyze proteins and certain polysaccharides including starch. The G+C content of 35.2 mol% is higher than other Tenacibaculum species, and the strains uniquely display endocellulase activity and growth on sucrose.

Key findings

• Tenacibaculum skagerrakense sp. nov. is a novel marine bacterial species isolated from pelagic seawater, distinguished from surface-associated Tenacibaculum species by its free-living lifestyle
• DNA-DNA hybridization values (35.9% with T. mesophilum, 34.3% with T. amylolyticum) well below the 70% species threshold supported the designation as a new species
• The novel strains possess unique characteristics including bright yellow pigmentation, endocellulase activity, higher G+C content (35.2 mol%), sucrose utilization, and enhanced salt tolerance compared to other Tenacibaculum species
• Both isolates (D28 and D30T) hydrolyze proteins and glucose polymers including starch, demonstrating enzymatic capabilities typical of surface-associated bacteria despite free-living origin