Brevibacterium rongguiense sp. nov., isolated from freshwater sediment.

A Gram stain-positive, non-spore-forming, non-motile and rod-shaped actinomycete, strain 5221T, was isolated from the sediment of a river collected at Ronggui in the Pearl River Delta, PR China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain formed a distinct lineage within the genus Brevibacterium and had the highest sequence similarity to Brevibacterium pityocampae Tp12T (96.7 %), followed by Brevibacterium daeguense 2C6-41T (96.5 %), Brevibacterium samyangense SST-8T (96.0 %) and Brevibacterium ravenspurgense 20T (95.9 %). The results of chemotaxonomic analyses, including detecting anteiso-C15 : 0, anteiso-C17 : 0, and C16 : 0 as the major cellular fatty acids, diphosphatidylglycerol, phosphatidylglycerol and three phosphoglycolipids as the polar lipids, MK-8(H2) as the major menaquinone, and a DNA G+C content of 72.4 mol%, supported that strain 5221T is a member of the genus Brevibacterium. Furthermore, low sequence similarities of 16S rRNA gene sequences, differences in fatty acid compositions and differential physiological characteristics such as enzyme activity and carbon sources utilization ability distinguished the isolate from its close relatives. Therefore, strain 5221T represents a novel species of the genus Brevibacterium, for which the name Brevibacterium rongguiense sp. nov. is proposed, with the type strain 5221T (=GDMCC 1.1766T=KACC 21700T).

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, F8825T, 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 MSSRFBL1T (99.4%), followed by C. thiooxidans F43bT (98.8%) and C. azotifigens A.slu09T (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 F8825T with MSSRFBL1T, respectively) confirmed that strain F8825T was a novel species, different from C. lividus MSSRFBL1T, C. thiooxidans F43bT, and C. azotifigens A.slu09T. 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 F8825T was identified as a novel species in the genus Ciceribacter, for which the name Ciceribacter ferrooxidans sp. nov. is proposed. The type strain is F8825T (= CCTCC AB 2018196T = KCTC 62948T).