Streptomyces chilikensis sp. nov., a halophilic streptomycete isolated from brackish water sediment.

A novel actinobacterial strain, designated RC 1830(T), was isolated from the sediment of estuarine coastal brackish water lagoon of Chilika Lake, in Khurdha district of Odisha, India, and characterized using a polyphasic approach. Strain RC 1830(T) was halophilic and alkali-tolerant and found to hydrolyse chitin, starch, tributyrin, lecithin, Tween 80, cellulose, gelatin and casein. The diagnostic presence of ll-diaminopimelic acid, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, C16 : 0, iso-C17 : 0, anteiso-C17 : 0 as major cellular fatty acids and MK-9(H4 and H6) as major menaquinones noticeably associated the strain to the genus Streptomyces. After comparison and analysis of the near complete 16S rRNA gene sequence with representative strains of other streptomycetes, it was evident that strain RC 1830(T) belonged to the genus Streptomyces, and exhibited the highest sequence similarities of 99.53 %, 99.25 %, 99.11 %, 99.10 % and 99. 06 % to Streptomyces fragilis DSM 40044(T), Streptomyces coelicoflavus NBRC 15399(T), Streptomyces flaveolus NBRC 3715(T), Streptomyces lavenduligrisesus NBRC 13405(T) and Streptomyces eurythermus ATCC 14975(T), respectively. Reconstruction of a phylogenetic tree for the genus Streptomyces revealed that strain RC 1830(T) formed a distinct phyletic line and clustered with its most closely related neighbour S. fragilis DSM 40044(T). The DNA-DNA relatedness values between strain RC 1830(T) and the most closely related type strain S. fragilis DSM 40044(T) were determined to be 17.7 ± 4.55 %. Additionally, morphological, biochemical and physiological tests were able to distinguish the strain from the most closely related type strain S. fragilis DSM 40044(T) and other closely related neighbours, S. coelicoflavus DSM 41471(T) and Streptomyces flaveolus DSM 40061(T). Based on a range of phenotypic and genotypic properties, strain RC 1830(T) is suggested to represent a novel species of the genus Streptomyces for which the name Streptomyces chilikensis sp. nov. is proposed. The type strain is RC 1830(T) ( = JCM 18411(T) = DSM 42072(T)).