Streptomyces cadmiisoli sp. nov., a novel actinomycete isolated from cadmium-contaminated soil.

A novel Streptomyces strain, ZFG47, isolated from a cadmium-contaminated soil sample, was taxonomically studied in detail. Strain ZFG47 formed long, flexuous spiral spore chains consisting of elliptoid spores with spiny surfaces. The cell-wall hydrolysates contained ll-diaminopimelic acid as the diagnostic diamino acid. The major menaquinones consisted of MK-9(H2), MK-9(H4) and MK-9(H8). The major polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol mannosides. The predominant cellular fatty acids were iso-C16 : 0, C16 : 0 and anteiso-C15 : 0. The 16S rRNA gene sequence-based phylogenetic analysis indicated that this strain belongs to the genus Streptomyces, showing the highest sequence similarity to Streptomyceskoyangensis VK-A60 (98.7 %). However, the digital DNA-DNA hybridization value, the average nucleotide identity value and the MLSA evolutionary distance between this strain and S. koyangensis VK-A60 showed that it belonged to a distinct species. Furthermore, the novel isolate could be distinctly differentiated from S. koyangensis VK-A60 by morphological, physiological and biochemical characteristics. On the basis of the evidence from this polyphasic study, it is concluded that strain ZFG47 represents a novel species of the genus Streptomyces, for which the name Streptomyces cadmiisoli sp. nov. is proposed, with strain ZFG47 (CICC 11050=JCM 32897) as the type strain.