Identification of Streptomyces and Kitasatospora strains from Thai soils with geldanamycin production strain

Abstract

Five strains of actinomycetes were isolated from soils in Thailand. PNK1–3, PNK1–5, TT2–9 and KN-6 were belonged to Streptomyces and FLM-2 was Kitasatospora based on their phenotypic and chemotaxonomic characteristics. Phylogenetic analysis using 16S rDNA sequences revealed that PNK1–3 and PNK1–5 were identified as S. hygroscopicus (99.7%), TT2–9 was closed to S. nogalater DSM 40546^T (98.0%), KN-6 was S. purpurascens (99.8%); and FLM-2 showed highest similarity with K. kifunensis LMG 19957^T (97.6%). The selected strain, PNK1–3 produced geldanamycin that showed inhibition on the growth of Gram-positive bacteria and strong cytotoxicity against KB and BC cells lines. Its taxonomic characterization has been described.