Pseudokordiimonas caeni gen. nov., sp. nov., isolated from activated sludge

A bacterial strain designated as LB-31^T was isolated from activated sludge. Strain LB-31^T was Gram-stain-negative, non-spore-forming and rod-shaped with a single polar flagellum. The isolate grew at 15-37 °C, pH 5.5-8.5 and 0.5-8.5 % (w/v) NaCl. Genome sequencing revealed a genome size of 3.55 Mb, a G+C content of 61.1 mol% and 3222 protein-coding genes. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain LB-31^T formed a phyletic lineage that was distinct from the three known genus within the family Kordiimonadaceae. The 16S rRNA gene sequence similarity of strain LB-31^T to all recognized bacterial species was no more than 94 %. Average nucleotide identity and digital DNA-DNA hybridization values between strain LB-31^T and its phylogenetic neighbours were below 72 and 22 %, respectively. The average amino acid identity values for strain LB-31^T and its closed phylogenetic neighbours Kordiimonas and Eilatimonas were below 63%, supporting that strain LB-31^T was a member of a novel genus. The predominant respiratory quinone is Q-10, the fatty acid profile predominantly consisted of iso-C_17 : 1  ω9c, iso-C_17 : 0, iso-C_15 : 0 and summed feature 3 (comprising iso-C_15 : 02-OH/C_16 : 1  ω7c), and the major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The combined genotypic and phenotypic data show that strain LB-31^T represents a novel species of a novel genus in the family Kordiimonadaceae, for which the name Pseudokordiimonas caeni gen. nov., sp. nov. is proposed. The type strain of Pseudokordiimonas caeni is LB-31^T (=GDMCC 1.3625^T=KCTC 92687^T).