Streptomyces beihaiensis sp. nov., a chitin- degrading actinobacterium, isolated from shrimp pond soil

A Gram- stain- positive actinobacterium, designated strain GXMU- J5(T), was isolated from a sample of shrimp pond soil collected in Tieshangang Saltern, Beihai, PR China. The morphological, chemotaxonomic and phylogenetic characteristics were consistent with its classification in the genus Streptomyces. The organism formed an extensively branched substrate mycelium, with abundant aerial hyphae that differentiated into spores. Phylogenetic analysis of 16S rRNA gene sequences showed that strain GXMU-J5(T) was most related to Streptomyces kunmingensis DSM 41681(T) (similarity 97.74 %) and Streptomyces endophyticus YIM 65594(T) (similarity 96.80 %). However, the values of digital DNA-DNA hybridization, average nucleotide identity and evolutionary distance of multilocus sequence analysis between strain GXMU- J5(T) and its closest relatives indicated that it represented a distinct species. Strain GXMU- J5(T) contained - ll-diaminopimelic acid and the major whole- cell hydrolysates were xylose and galactose. The predominant menaquinones of strain GXMU- J5(T) were revealed as MK- 9(H4), MK- 9(H6) and MK- 9(H8). The polar lipids consisted of diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol mannosides and phospholipids of unknown structure containing glucosamine. The predominant cellular fatty acids were iso- C-15:0, anteiso-C-15:0, iso-C-16:0, iso-C-17: 0 and anteiso- C-17:0. The whole genome size of strain GXMU- J5(T) was 6.79 Mbp with a 71.39 mol% G+C content. Genomic analysis indicated that strain GXMU- J5(T) had the potential to degrade chitin. On the basis of these genotypic and phenotypic data, it is supported that strain GXMU- J5(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces beihaiensis sp. nov. is proposed. The type strain is strain GXMU- J5(T) (=MCCC 1K08064(T)=JCM 35629(T)).