Stagnihabitans lacustris sp. nov., an Anoxygenic Photoheterotrophic Bacterium of the Family Paracoccaceae, Isolated from a Eutrophic Pond in Czechia

A novel photoheterotrophic, beige-pigmented, bacteriochlorophyll a-containing strain KR11T was isolated from Kaprový pond in Třeboň, Czechia. KR11T cells were Gram-negative, rod-shaped, and motile. The isolated strain grew under photoheterotrophic conditions between 20 and 40 °C (optimum 22–25 °C), at pH ranges from 6.0 to 9.0 (optimum 7.0). It did not require NaCl for growth but tolerated NaCl concentrations up to 1.5% (w/v). No growth was observed under photoautotrophic conditions. Strain KR11T showed the highest 16S rRNA gene sequence similarity to the type strains of Stagnihabitans tardus CYK-10T (98.84%), Tabrizicola fusiformis SY72T (95.95%), and Rhodobacter sediminis N1T (95.37%). Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain KR11T clusters within the genus Stagnihabitans in the family Paracoccaceae of class Alphaproteobacteria. The whole-genome sequence of strain KR11T comprises 4,085,976 bp with a 65 mol% G+C content. Phylogenomic analysis, including core-genome phylogeny, and the low genomic similarity (<95% ANI and <70% dDDH) to phylogenetically related taxa confirmed the taxonomic separation of strain KR11T at the species level. The distinctive phenotypic traits, chemotaxonomic studies, phylogenetic, and genomic analysis establish strain KR11T as a novel species within the genus Stagnihabitans. Accordingly, we propose the name Stagnihabitans lacustris sp. nov. KR11T (=CCUG 74777T, LMG 31924T), isolated from fresh water.