Alteromonas pelagimontana sp nov., a marine exopolysaccharide-producing bacterium isolated from the Southwest Indian Ridge

A novel exopolysaccharide-producing strain, designated as 5.12(T), was isolated from a sediment sample from the Southwest Indian Ridge, Indian Ocean. The strain was Gram-stain-negative, motile, strictly aerobic, and oxidase-and catalase-positive. It grew optimally at 35 degrees C, at pH 6.0 and in the presence of 3.5% (w/v) NaCl. Its major isoprenoid quinone was ubiquinone-8 (Q-8) and summed feature 3 (comprising C-16 : 1 omega 6c and/ or C-16 : 1 omega 7c), C-16 : 0 and C-18 : 1 omega 7c were the major cellular fatty acids. The DNA G+C content was 46.1 mol%. 16S rRNA gene sequence analysis suggested that strain 5.12(T) is a member of the genus Alteromonas. Strain 5.12(T) exhibited close 16S rRNA gene sequence similarity to Alteromonas lipolytica JW12(T) (96.1 %), Alteromonas hispanica F-32(T) (95.9 %), Alteromonas confluentis DSSK2-12(T) (95.9 %), Alteromonas litorea TF-22(T) (95.6 %) and Alteromonas mediterranea DET (95.5 %). Strain 5.12(T) contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. Owing to significant differences in the 16S rRNA gene sequences, as well as the phenotypic and chemotaxonomic characteristics, the novel isolate described here merits classification as a representative of a novel species of the genus Alteromonas, for which the name Alteromonas pelagimontana sp. nov. is proposed. The type strain of this species is 5.12(T) (LMG 29661(T)= MCC 3250(T)).