Marinobacter algicola sp. nov., isolated from laboratory cultures of paralytic shellfish toxin-producing dinoflagellates

Abstract

Phylogenetic and phenotypic analysis of cultivable marine bacteria isolated from laboratory cultures of two paralytic shellfish toxin-producing dinoflagellates, Gymnodinium catenatum and Alexandrium tamarense, showed the presence of a novel group of Gram-negative, aerobic, moderately halophilic and hydrocarbon-degrading bacteria, related to the genus Marinobacter. The strains, designated DG893^T, DG1136 and ATAM407-13, grew optimally in media with 3–6 % NaCl and at 25–30 °C, and all could utilize n-hexadecane and n-tetradecane as the sole carbon source. The strains had a 16S rRNA gene sequence similarity of 94·2–94·3 % to Marinobacter hydrocarbonoclasticus ATCC 27132, and a similarity of 97·5–97·8 % to the closest phylogenetically related type strain, Marinobacter flavimaris DSM 16070^T. DNA–DNA hybridization levels to M. flavimaris and other Marinobacter type strains were ⩽42 %, while DNA–DNA reassociation values among DG893^T, DG1136 and ATAM407-13 were ⩾83 %. The DNA G+C content was 54–55 mol% and the major isoprenoid quinone was ubiquinone-9. On the basis of phenotypic, chemotaxonomic, DNA–DNA hybridization and phylogenetic analysis, it is proposed that these three strains represent a novel species, Marinobacter algicola sp. nov. The type strain is DG893^T (=DSM 16394^T=NCIMB 14009^T).