Hephaestia caeni gen. nov., sp nov., a novel member of the family Sphingomonadaceae isolated from activated sludge

A Gram-staining-negative, rod-shaped and motile bacterium, designated strain ERB1-3(T), was isolated from a laboratory-scale activated sludge system treating coke plant effluent using thiocyanate-supplemented growth medium. Strain ERB1-3(T) was oxidase-positive and weakly catalase-positive. The predominant fatty acids were C-18:1 omega 7c (35.6%) and C-17:1 omega 6c (29.2%), and the major respiratory quinone was Q-10. Polar lipids were dominated by sphingoglycolipid and phosphatidylglycerol. Major polyamines were spermidine and sym-homospermidine. The G+C content of the genomic DNA of strain ERB1-3(T) was 66.4 molok. Based on the 16S rRNA gene, strain ERB1-3(T) exhibited the highest sequence similarity values to Sphingomonas sanxanigenens DSM 19645(T) (96.1%), Sphingobium scionense DSM 19371(T) (95.1 WO) and Stakelama pacifica LMG 24686(T) (94.8%) within the family Sphingomonadaceae. The novel isolate had some unique chemotaxonomic features that differentiated it from these closely related strains, contained much more C-17:1 omega 6c, C(15:0)2-OH, C-17:0 and C-17:1 omega 8c fatty acids and possessed diphosphatidylglycerol only in trace amounts. On the basis of the phenotypic, chemotaxonomic and molecular data, strain ERB1-3(T) is considered to represent a novel genus and species, for which the name Hephaestia caeni gen. nov., sp. nov. is proposed. The type strain is ERB-3(T) (=DSM 25527(T)=NCAIM B 02511(T)).