Two novel strains isolated from a brackish lake constitute Aeoliella fuhlenseeensis sp. nov. and Bythopirellula superficialaquae sp. nov. in the family Lacipirellulaceae

Abstract The strain collection of Heinz Schlesner (Kiel University, Germany) largely consists of budding bacteria collected from the 1980s to early 2000s. It still holds an untapped diversity of bacteria with uncommon morphologies and cell division modes. Here, we characterize two strains from his collection, SH292 T and SH678 T , that he isolated from Lake Fuhlensee, a slightly brackish lake in Northern Germany. Phylogenetic tree reconstruction places the novel strains in the family Lacipirellulaceae within the phylum Planctomycetota . More detailed analyses based on five phylogenetic markers suggest positions within the genera Aeoliella and Bythopirellula , respectively. The novel isolates have an aerobic and heterotrophic lifestyle and a mesophilic and neutrophilic growth profile. Optimal growth was observed at 25 °C and pH 7.0–7.5. Genome sequencing revealed slightly smaller genomes of 5.6–6.0 Mbp compared to those of the close relatives (6.1–7.8 Mbp). An analysis of genome-encoded features suggests differences in the portfolio of secondary metabolite-associated biosynthetic gene clusters and carbohydrate-active enzymes. Genomic and morphological differences support the results of the phylogenetic inferences that together delineate the novel strains from previously described species. Hence, we conclude that the two novel isolates belong to two novel species, for which we introduce the names Aeoliella fuhlenseeensis sp. nov. and Bythopirellula superficialaquae sp. nov. The novel taxa are represented by strains SH292 T (= DSM 116587 T = KCTC 102092 T ) and SH678 T (= DSM 116729 T = KCTC 102079 T ) as the corresponding type strains.