Comamonas flocculans sp. nov., a Floc-Forming Bacterium Isolated from Livestock Wastewater.

A Gram-negative, aerobic, non-motile, rod-shaped, floc-forming, and non-spore-forming bacterium, designated as NLF-7-7, was isolated from the biofilm of a sample collected from a livestock wastewater treatment plant in Nonsan, Republic of Korea. Strain NLF-7-7, forms a visible floc and grows in the flocculated state. Cells of strain NLF-7-7 grew optimally at pH 6.5 and 30 °C and in the presence of 0.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NLF-7-7 belonged to the family Comamonadaceae, and was most closely related to Comamonas badia DSM 17552 (95.8% similarity) and Comamonas nitrativorans 23310 (94.0% similarity). The phylogenetic and phenotypic data indicate strain NLF-7-7 is clearly distinguished from the Comamonas lineage. The major cellular fatty acids were C 3OH, C, and summed feature 3 (C ω6c/C ω7c). The respiratory quinone was Q-8. The polar lipids were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. The DNA G+C content of strain NLF-7-7 was 68.0 mol%. Based on the phenotypic, chemotaxonomic, and phylogenetic properties, strain NLF-7-7 represents a novel species of the genus Comamonas, for which the name Comamonas flocculans sp. nov. is proposed. The type strain is C. flocculans NLF-7-7 (=KCTC 62943). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Comamonas flocculans NLF-7-7 is MN527436. The whole-genome shotgun BioProject Number is PRJNA555370 with the Accession Number CP042344.