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

Abstract

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-C 15 : 0 , anteiso-C 15 : 0 , iso-C 16 : 0 , C 16 : 0 , iso-C 17 : 0 , anteiso-C 17 : 0 as major cellular fatty acids and MK-9(H 4 and H 6 ) 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 ).