Dechloromonas parva sp. nov., a Member of the Family Azonexaceae

A Dechloromonas-like bacterial strain, designated HYN0024^T, was isolated from lake water, and its taxonomic status was characterized in this study. Although the bacterium was isolated from an aerobic water sample, its cells were facultative anaerobes utilizing Fe(III) and oxygen as terminal electron acceptors. Phylogenetic analysis based on both genome and 16S rRNA gene sequences indicated that strain HYN0024^T belongs to the family Azonexaceae and forms a monophyletic clade with the type strains of Ferribacterium limneticum, Quatrionicoccus australiensis, and 'Dechloromonas aromatica'. However, the type strains of the genera Ferribacterium and Quatrionicoccus are currently unavailable from any public culture collections. Among the available type strains with validly published names, Dechloromonas hortensis shared the highest 16S rRNA gene sequence similarity (98.35%) with strain HYN0024^T, but their average nucleotide identity (80.13%) was below the threshold for species delineation. The biochemical and physiological features also supported the distinctiveness of the isolate from previously known species. The 16S rRNA gene sequence similarity, genomic relatedness, phylogenetic tree topology, and phenotypic characteristics supported the taxonomic independence of the isolate as a novel species in the genus Dechloromonas. Based on the phylogenetic and polyphasic taxonomic data presented in this study, we propose a novel species, Dechloromonas parva sp. nov., for strain HYN0024^T (= KACC 19179^T = NBRC 112737^T).