Cellulosimicrobium marinum sp. nov., an actinobacterium isolated from sea sediment

A novel Gram stain positive actinobacterium, designated RS-7-4T, was isolated from a sea sediment sample collected in Indonesia, and its taxonomic position was investigated using a polyphasic approach. Strain RS-7-4T was observed to form vegetative hyphae in the early phase of growth, but the hyphae eventually fragmented into short rods to coccoid cells. Growth occurred at 15–37 °C, pH 6.0–11.0 and in the presence of 0–7 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain RS-7-4T was closely related to the members of the genus Cellulosimicrobium, with a similarity range of 98.08–99.10 %. The peptidoglycan type of strain RS-7-4T was found to be A4α l-Lys–l-Thr–d-Asp. The predominant menaquinone was MK-9(H4), and the major fatty acids were anteiso-C15:0, iso-C15:0 and anteiso-C17:0. The DNA G+C content was 75.6 mol%. These chemotaxonomic features corresponded to those of the genus Cellulosimicrobium. Meanwhile, the results of DNA–DNA hybridization, and physiological and biochemical tests revealed that strain RS-7-4T was different from the recognized species of the genus Cellulosimicrobium. Therefore, strain RS-7-4T represents a novel species of the genus Cellulosimicrobium, for which the name Cellulosimicrobium marinum sp. nov. is proposed. The type strain is RS-7-4T (=NBRC 110994T =InaCC A726T).