sp. nov., a home for novel actinobacteria isolated from stable foams on activated sludge wastewater treatment plants.

The taxonomic status of two strains, designated BEN371 and CON9, isolated from stable foams on activated sludge plants was the subject of a polyphasic study which also included the type strains of species and three authenticated strains recovered from such foams. Phylogenetic analyses of 16S rRNA gene sequences showed that these isolates formed a compact cluster suggesting a well-supported lineage together with a second branch containing the strains. A phylogenomic tree based on sequences of 92 core genes extracted from whole genome sequences of the isolates, the strains and type strains confirmed the assignment of the isolates and the strains to separate but closely associated lineages. Average nucleotide index (ANI) and digital DNA-DNA hybridisation (dDDH) similarities showed that BEN371 and CON9 belonged to the same species and had chemotaxonomic and morphological features consistent with their assignment to the genus . The isolates and the strains were distinguished using a range of phenotypic features and by low ANI and dDDH values of 84.2 and 27.0 %, respectively. These data supplemented with associated genome characteristics show that BEN371 and CON9 represent a novel species of the genus . The name proposed for members of this taxon is sp. nov. with isolate CON9 (=DSM 43602=JCM 35249) as the type strain.