Description of Ectothiorhodospira salini sp. nov.

Abstract

Strain JA430^T is a Gram-negative, vibrioid to spiral shaped phototrophic purple sulfur bacterium isolated from anoxic sediment of a saltern at Kanyakumari in a mineral salts medium that contained 2% NaCl (w/v). Strain JA430^T grows optimally at 5−6% NaCl and tolerates up to 12% NaCl. Intracellular photosynthetic membranes were of the lamellar type. Bacteriochlorophyll a and carotenoids of the spirilloxanthin series are present as photosynthetic pigments. Major cellular fatty acids are C_18:1ω7c, C_16:0, C_19:0cycloω8c and C_16:1ω7c/C_16:1ω6c. Strain JA430^T exhibits photoorganoheterotrophy and chemoorganoheterotrophy and requires para-aminobenzoic acid, pantothenate and pyridoxal phosphate for growth. Phylogenetic analysis on the basis of 16S rRNA gene sequence analysis showed that strain JA430^T forms monophyletic group in the genus Ectothiorhodospira. The highest sequence similarity for strain JA430^T was found with the type strains of Ectothiorhodospira variabilis DSM 21381^T (96.1%) and Ectothiorhodospira haloalkaliphila ATCC 51935^T (96.2%). Morphological and physiological characteristics discriminate strain JA430^T from other species of the genus Ectothiorhodospira, for which we describe this as a novel species, Ectothiorhodospira salini sp. nov. ( = NBRC 105915^T = KCTC 5805^T).