Pseudoalteromonas arabiensis sp. nov., a marine polysaccharide-producing bacterium

A novel exopolysaccharide-producing bacterium, designated strain k53(T), was isolated from sediment from the Arabia Sea, Indian Ocean. The strain was Gram-negative, motile, strictly aerobic, oxidase-positive and catalase-positive, and required Na(+) for growth. Its major isoprenoid quinone was ubiquinone-8 (Q-8), and its cellular fatty acid profile mainly consisted of C16 : 1ω7c, C16 : 0 and C18 : 1ω7c. The DNA G+C content was 43 mol%. 16S rRNA gene sequence analysis suggested that strain k53(T) is a member of the genus Pseudoalteromonas. Strain k53(T) exhibited close phylogenetic affinity to Pseudoalteromonas lipolytica LMEB 39(T) (98.0% 16S rRNA gene sequence similarity) and Pseudoalteromonas donghaensis HJ51(T) (97.3 %).The DNA-DNA reassociation values between strain k53(T) and P. lipolytica JCM 15903(T) and P. donghaensis LMG 24469(T) were 17 % and 12 %, respectively. Owing to the significant differences in phenotypic and chemotaxonomic characteristics, and phylogenetic analysis based on the 16S rRNA gene sequence and DNA-DNA relatedness data, the isolate merits classification as a representative of a novel species, for which the name Pseudoalteromonas arabiensis is proposed. The type strain of this species is k53(T) ( = JCM 17292(T) = NCIMB 14688(T)).