Ciceribacter ferrooxidans sp. nov., a nitrate-reducing Fe(II)-oxidizing bacterium isolated from ferrous ion-rich sediment.

A nitrate-reducing Fe(II)-oxidizing bacterial strain, F8825(T), was isolated from the Fe(II)-rich sediment of an urban creek in Pearl River Delta, China. The strain was Gram-negative, facultative chemolithotrophic, facultative anaerobic, non-spore-forming, and rod-shaped with a single flagellum. Phy-logenetic analysis based on 16S rRNA gene sequencing indicated that it belongs to the genus Ciceribacter and is most closely related to C. lividus MSSRFBL1(T) (99.4%), followed by C. thiooxidans F43b(T) (98.8%) and C. azotifigens A.slu09(T) (98.0%). Fatty acid, polar lipid, respiratory quinone, and DNA G + C content analyses supported its classification in the genus Ciceribacter. Multilocus sequence analysis of concatenated 16S rRNA, atpD, glnII, gyrB, recA, and thrC suggested that the isolate was a novel species. DNA-DNA hybridization and genome sequence comparisons (90.88 and 89.86%, for values of ANIm and ANIb between strains F8825(T) with MSSRFBL1(T), respectively) confirmed that strain F8825(T) was a novel species, different from C. lividus MSSRFBL1(T), C. thiooxidans F43b(T), and C. azotifigens A.slu09(T). The physiological and biochemical properties of the strain, such as carbon source utilization, nitrate reduction, and ferrous ion oxidation, further supported that this is a novel species. Based on the polyphasic taxonomic results, strain F8825(T) was identified as a novel species in the genus Ciceribacter, for which the name Ciceribacter ferrooxidans sp. nov. is proposed. The type strain is F8825(T) (= CCTCC AB 2018196(T) = KCTC 62948(T)).