Dethiosulfatarculus sandiegensis gen. nov., sp nov., isolated from a methanogenic paraffin-degrading enrichment culture and emended description of the family Desulfarculaceae

A mesophilic deltaproteobacterium, designated strain SPRT, was isolated from a methanogenic consortium capable of degrading long-chain paraffins. Cells were motile, vibrio-shaped, and occurred singly, in pairs or in clusters. Strain SPRT did not metabolize hydrocarbons but grew fermentatively on pyruvate and oxaloacetate and autotrophically with H-2 and CO2. Thiosulfate served as a terminal electron acceptor, but sulfate or sulfite did not. The organism required at least 10 g NaCl l(-1) and a small amount of yeast extract (0.001%) for growth. Optimal growth was observed between 30 and 37 degrees C and a pH range from 6.0 to 7.2. The DNA G + C content of SPRT's genome was 52.02 mol%. Based on 16S rRNA gene sequence analysis, strain SPRT was distinct from previously described Deltaproteobacteria, exhibiting the closest affiliation to Desulfarculus baarsii DSM 2075(T) and Desulfocarbo indianensis SCBMT, with only 91% similarity between their respective 16S gene sequences. In silico genome comparison supported the distinctiveness between strain SPRT and both Desulfocarbo indianensis SCBMT and Desulfarculus baarsii DSM 2075(T). Based on physiological differences, as well as phylogenetic and genomic comparisons, we propose to classify SPRT as the type strain (=DSM 100305(T)=JCM 30857(T)) of a novel species of a new genus with the name Dethiosulfatarculus sandiegensis gen. nov., sp. nov.