Streptomyces guryensis sp. nov. exhibiting antimicrobial activity, isolated from riverside soil

A novel Gram-stain-positive, aerobic actinobacterial strain designated NR30^T was isolated from riverside soil. A polyphasic approach was employed for the taxonomic characterization of NR30^T. The strain developed extensively branched light brown to light pink substrate mycelia and light grey aerial mycelia, and produced spiny spores in loose spiral spore chains on ISP 3 and 4 agars. NR30^T grew at 10-40°C (optimum, 30°C), at pH 6.0-9.0 (optimum, pH 8.0) and in the presence of 0-3 % NaCl (optimum, 0 %). Analysis of 16S rRNA gene sequences indicated that NR30^T represents a member of the genus Streptomyces. NR30^T shared the highest 16S rRNA gene sequence similarity with Streptomyces cyaneus NRRL B-2296^T (98.6 %). On the basis of orthologous average nucleotide identity, NR30^T was most closely related to Streptomyces panaciradicis NBRC 109811^T with 86.3 % identity. The results of the digital DNA-DNA hybridization analysis also indicated low levels of relatedness with other species, as the highest value was observed with Streptomyces panaciradicis NBRC 109811^T (31.1 %). The major fatty acids of the strain were anteiso-C_15 : 0, C_16 : 0, iso-C_16 : 0 and anteiso-C_17 : 0. The major respiratory quinones were MK-9(H₈) and MK-9(H₆). The diagnostic polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol mannoside. The major cell wall diamino acid was ll-diaminopimelic acid, and the characteristic whole-cell sugars were rhamnose, ribose and glucose. The DNA G+C content was 70.3 mol %. NR30^T exhibited antimicrobial activity against several Gram-negative bacteria and yeasts. On the basis of the results of both phenotypic and phylogenetic analyses, strain NR30^T evidently represents a novel species of the genus Streptomyces, and the name Streptomyces guryensis sp. nov. (type strain=NR30^T =KCTC 49653^T=LMG 32476^T) is proposed accordingly.