Abstract
Four budding and pink-pigmented planctomycetal strains, designated SH449(T), SH551(T), SH467(T), and SH501(T), were isolated from diverse environmental sources, including Fjord Schlei (a 42 km brackish arm of the Baltic Sea), ponds and wastewater lagoons in Northern Germany, as part of an isolation campaign led by Heinz Schlesner at Kiel University between the 1980s and early 2000s. Analyses based on five phylogenetic markers indicate that these strains constitute a novel genus within the family Pirellulaceae of the phylum Planctomycetota. All four strains are aerobic, heterotrophic, mesophilic, and exhibit neutrophilic properties. Strains SH551(T) and SH501(T) possess at least one plasmid that is not present in the other two strains. Genome analyses revealed that their genomes are of comparable size to those of other members of the Pirellulaceae family, exhibiting a DNA G + C content ranging from 49 to 54%. Analysis of predicted biosynthetic gene clusters shows that all four strains possess the genetic potential to produce bioactive compounds and may therefore be regarded as putative “talented producers”. The polyphasic approach places all four novel strains in a new genus within the family Pirellulaceae, for which the name Brakhagea gen. nov. is proposed. The novel isolates represent four distinct novel species, Brakhagea baltica sp. nov. (type strain SH449(T) = KCTC 102025(T) = DSM 116586(T)), Brakhagea lacunae sp. nov. (type strain SH551(T) = KCTC 102023(T) = DSM 116785(T) = CECT 30846(T)), Brakhagea slesvicensis sp. nov. (type strain SH467(T) = KCTC 102026(T) = DSM 116378(T)), and Brakhagea aquatica sp. nov. (type strain SH501(T) = DSM 102088(T) = CECT 30906(T)). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-47393-x.