A Gram-stain-negative, non-motile and short-rod-shaped bacterium, designated as strain SY7(T), was isolated from rhizosphere soil of the mangrove Kandelia obovata of Fugong village, in Zhangzhou, China. The isolate grew at 10-45 degrees C (optimum 30 degrees C), pH 6.0-10.0 (optimum pH 7.0) and 0-8% NaCl (optimum 3%, w/v). The 16S rRNA gene sequence and phylogenetic analysis revealed that strain SY7(T) located within the radiation of genus Nitratireductor and showed the highest sequence similarity of 97.23% to Nitratireductor pacificus MCCC 1A01024(T). The DNA G+C content was 64.9%. In silico DNA-DNA hybridization and average nucleotide identity values between strain SY7(T) with reference strains of N. pacificus MCCC 1A01024(T), N. basaltis KCTC 22119(T) and N. aquibiodomus DSM 15645(T) were 16.7%, 14.3%, 14.7% and 75.2%, 72.6%, 73.5%, respectively. The major isoprenoid quinone was Q-10. The dominant fatty acids were 11-methyl C-18:1 omega 7c, iso-C-17:0, C-19:0 omega 8c cyclo and summed feature 8 (C-18:1 omega 6c/C-18:1 omega 7c), a profile that almost matched the other members of the genus Nitratireductor. The predominant polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol. On the basis of the phenotypic, phylogenetic and chemotaxonomic analysis, strain SY7(T) represents a novel species of the genus Nitratireductor, for which the name Nitratireductor mangrovi sp. nov., is proposed. The type strain is SY7(T) (= KCTC 72110(T) = MCCC 1K03723(T)).