sp. nov., a novel actinobacterium isolated from lake sediment.

A novel actinobacterium, designated strain H8750, was isolated from sediment sampled at Lugu Lake, southwest PR China and its polyphasic taxonomy was studied. Strain H8750 produced well-developed substrate mycelium, and formed club-shaped and hooked structures borne on the tip of the aerial mycelia. It contained -diaminopimelic, glucose, ribose and madurose in whole-cell hydrolysates. The predominant menaquinones were MK-9(H), MK-9(H) and MK-9(H). The phospholipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, unidentified phospholipids and unidentified aminophospholipids. The major fatty acid (>10 %) were 9 C, iso-C and C. The DNA G+C content was 69.7 mol% based on the whole genome sequence. Phylogenetic analysis based on 16S rRNA gene and whole-genome sequences indicated that strain H8750 was closely related to JCM 10982 (98.0 %), JCM 10983 (97.9 %) and DSM 45867 (97.8 %) and formed a monophyletic clade within the genus in the phylogenetic trees. The average nucleotide identity and digital DNA-DNA hybridization values between strain H8750 and its closely related species were 79.887.2 % and 25.928.0 %, respectively, which showed that it belonged to a distinct species. Furthermore, the morphological and phenotypic characteristics allowed the isolate to be differentiated from its closely related species. Therefore, it is concluded that strain H8750 can be classified as representing a novel species of the genus , for which the name sp. nov. is proposed. The type strain is H8750 (=JCM 34849=CICC 25116). Moreover, based on the gene prediction results, strain H8750 may have the genetic potential to synthesize many new secondary metabolites, which further increases its bioactive value.