Streptomyces acidicola sp. nov., isolated from a peat swamp forest in Thailand.

A novel actinobacterium, designated strain K1PN6, was isolated from soil sample collected in Kantulee peat swamp forest, Surat Thani province, Thailand. The morphological, chemotaxonomic, and phylogenetic characteristics were consistent with its classification in the genus Streptomyces. Based on 16S rRNA gene sequence analysis, strain K1PN6 showed highest similarity to Streptomyces phyllanthi PA1-07 (98.6 %), Streptomyces spongiae Sp080513SC-24 (98.3%) and Streptomyces adustus WH-9 (98.3%). The G + C content of the genomic DNA was 70.3 mol%. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain K1PN6 with S. phyllanthi TISTR 2346 (33.7 and 89.1%), S. spongiae NBRC 106415 (38.6 and 90.6%) and S. adustus NBRC 109810 (26.0 and 86.2%) were below the thresholds of 70 and 95-96% for prokaryotic conspecific assignation. Chemotaxonomic data revealed that strain K1PN6 possessed MK-9(H) (45%) and MK-9(H) (34%) as the predominant menaquinones. It contained LL-diaminopimelic acid as the diagnostic diamino acid and galactose, glucose, mannose, and ribose as whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, two unidentified aminolipids, an unidentified phospholipid, and glycophospholipid. The predominant cellular fatty acids (>10%) were iso-C, C, anteiso-C, and iso-C. On the basis of these genotypic and phenotypic data, strain K1PN6 should be designated as a representative of a novel species of the genus Streptomyces, for which the name Streptomyces acidicola sp. nov. is proposed with the type strain K1PN6 (=TBRC 11341=NBRC 114304).