Roseomonas aestuarii sp. nov., a bacteriochlorophyll-a containing alphaproteobacterium isolated from an estuarine habitat of India.

Two strains (JC17(T) and JC19a) of orange pigmented bacteria were isolated from an estuarine sample. Cells of both the strains were Gram-negative coccobacilli, non-motile, non-spore forming and strictly aerobic. Chemo-organoheterotrophy was the growth mode for both strains and was possible on a wide range of organic compounds. Strains were non-hemolytic and contained low levels of BChl-a and carotenoids. The fatty acids (>1.0%) comprised C(18:1)omega7c, C(16:1)omega7c/iso-C(15:0)2OH, C(16:0), C(16:0) 3-OH, C(18:1)2OH, C(16:1)omega5c, and C(19:0) cycloomega8c. The genomic DNA G+C content of strain JC17(T) was 66.2mol%. A phylogenetic tree based on 16S rRNA gene sequence analysis showed that strains JC17(T) and JC19a had the highest similarity to members of the genus Roseomonas and were closely related to Roseomonas cervicalis CIP104027(T) (96.4%) and Roseomonas ludipueritiae CIP107418(T) (96.3%) of the family Acetobacteraceae within the class Alphaproteobacteria. Strains JC17(T) and JC19a shared 100% 16S rRNA gene sequence similarity, were phenotypically (morphological, physiological, biochemical characters) identical and had closely related genomes (85% DDH). Based on polyphasic taxonomic data, strain JC17(T) is classified as a novel species of the genus Roseomonas for which the name Roseomonas aestuarii sp. nov. is proposed. The type strain is JC17(T) (=CCUG 57456(T) =KCTC 22692(T) =NBRC105654(T)).