Polyphasic taxonomic description of Streptomyces balliae sp. nov. and Streptomyces schrempfiae sp. nov.

Abstract Strains DSM 116793 T (JZT14 T = CECT 31213 T ) and DSM 118148 T (= KCTC 59415 T = unkn41448C T ), deposited in the DSMZ culture collection, were subjected to modern polyphasic taxonomic studies to determine their taxonomic positions. Strains DSM 116793 T and DSM 118148 T showed 16S rRNA gene sequence similarity values of 97.8% and 99.5% to the type strains of Streptomyces sulfonofaciens and Streptomyces bungoensis , respectively, supporting their assignment to the genus Streptomyces . Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between the genomes of strains DSM 116793 T and DSM 118148 T and their closest phylogenetic relatives were below the accepted species delineation thresholds of 70% for DDH and 95–96.7% for ANI, respectively. Morphological and phenotypic characteristics distinguished the strains from their closest relatives. Based on these data, strains DSM 116793 T and DSM 118148 T represent two novel species, for which the names Streptomyces balliae sp. nov. and Streptomyces schrempfiae sp. nov. are proposed, respectively. Crude extracts of strains DSM 116793 T and DSM 118148 T exhibited antibacterial activity against Gram-negative bacteria ( E. coli Δ tolC JW5503-1, P. vulgaris DSM 2140) and Gram-positive bacteria ( E. faecium DSM 20477 T and methicillin-resistant Staphylococcus aureus DSM 18827). Genome mining of biosynthetic gene clusters (BGCs) associated with secondary metabolites revealed multiple clusters with low similarity to known BGCs, indicating the presence of biosynthetic potential that warrants further investigation.