Paludibacterium denitrificans sp. nov., a Novel Denitrifying Bacterium Isolated from Activated Sludge

A Gram-reaction-negative, facultatively aerobic, motile, non-spore-forming, rod-shaped, and denitrifying bacterium, designated dN18-1 T , was isolated from activated sludge, Republic of Korea. This bacterium was investigated via a polyphasic approach to reveal its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain dN18-1 T belongs to the genus Paludibacterium and is most closely related to P. purpuratum KCTC 42852 T (96.2% sequence similarity), P. yongneupense KACC 11601 T (96.1%), and P. paludis BCRC 80514 T (95.2%). The average nucleotide identity values and digital DNA-DNA hybridization values calculated between strain dN18-1 T and the closely related strains were 72.5–73.1% and 19.0–19.6%. The genome comprises of 3,347,996 bp with a G + C content of 57.3 mol%. Strain dN18-1 T possesses ubiquinone Q-8 as a predominant respiratory quinone, and summed feature 3 (C 16:1 ω 6 c and/or C 16:1 ω 7 c ), summed feature 8 (C 18:1 ω 6 c /C 18:1 ω 7 c ), C 16:0 and C 12:0 , as its major fatty acids (>5%). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and four unidentified aminophospholipids. The results of ANI calculation, digital DNA-DNA hybridization, physiological and biochemical tests allowed phenotypic differentiation of strain dN18-1 T from rephrase other genus Paludibacterium species with validly published names. Therefore, this isolate represents a novel species, for which the name Paludibacterium denitrificans sp. nov. (type strain dN18-1 T = KACC 19537 T = CGMCC 1.16961 T ) is proposed.