Thioclava nitratireducens sp nov., isolated from surface seawater

A bacterial strain, designated 25B10_4(T), was isolated from surface seawater of the Bering Sea and characterized using a polyphasic taxonomic approach. Cells of strain 25B10_4(T) were Gram-stain-negative, motile and short-rod-shaped. Growth was observed at 10-43 degrees C (optimum 28 degrees C), at pH 6-9 (optimum pH 7) and with 0-12% NaCl (optimum 3-4 %, w/v). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 25B10_4(T) formed an independent branch within the genus Thioclava, sharing high similarities with four related type strains, Thioclava atlantica 13D2W-2(T) (98.9 %), Thioclava pacifica TL 2(T) (98.5 %), Thioclava dalianensis DLFJ1-1(T) (98.4 %) and Thioclava indica DT23-4(T) (96.9 %), and low similarities (less than 96.5 %) with other type strains within the family Rhodobacteraceae. The major fatty acid was identified as summed feature 8 (C-18:1 omega 6c and/or C-18:1 omega 7c). The quinone was Q-10. The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, glycolipid and five unidentified phospholipids. The DNA G+C content was 63.8 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between strain 25B10_4(T) and the four above-mentioned type strains were, respectively, 20.5-25.7% and 77.8-82.4 %. The phenotypic, phylogenetic and chemotaxonomic analyses clearly indicated that strain 25B10_4(T) represents a novel species within the genus Thioclava, for which the name Thioclava nitratireducens sp. nov. is proposed. The type strain is 25B10_4(T) (=MCCC 1A07302(T)=LMG 29614(T)).