Simplicispira hankyongi sp. nov., a novel denitrifying bacterium isolated from sludge

A Gram-stain-negative, facultatively anaerobic, motile, light-yellow, and rod-shaped bacterium, designated as NY-02^T, was isolated from the sludge of a wastewater treatment plant in Hanam City, Republic of Korea. The comparison of 16S rRNA gene sequences revealed that the strain formed a distinct lineage within the genus Simplicispira and was most closely related to S. suum SC1-8^T (99.0%), S. limi EMB325^T (98.3%), S. psychrophila LMG 5408^T (98.2%), and S. piscis RSG39^T (97.4%). Both average nucleotide identity (ANI) and DNA-DNA hybridization (DDH) values between strain NY-02^T, and its closes type strains [S. suum SC1-8^T, S. limi EMB325^T, S. psychrophila LMG 5408^T, and S. piscis RSG39^T] were lower than the cut-off (≥ 95-96% for ANI and ≥ 70% for DDH) to define a bacterial species. The genome comprises of 3,709,074 bp with a G + C content of 64.2 mol%. Ubiquinone 8 (Q-8) was the predominant quinone. The major fatty acids were C_16:0 and summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), and the major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylethanolamine. The results of the physiological, biochemical, and taxonomic analyses in addition to low ANI and DNA-DNA relatedness values (82.2% and < 34.0%, respectively) indicate that the strain NY-02^T represents a novel species of the genus Simplicispira. The name proposed for strain NY-02^T (= KACC 19731^T = LMG 31165^T) is Simplicispira hankyongi sp. nov.