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 SPR ^T , 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 SPR ^T did not metabolize hydrocarbons but grew fermentatively on pyruvate and oxaloacetate and autotrophically with H ₂ and CO ₂ . 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 °C and a pH range from 6.0 to 7.2. The DNA G+C content of SPR ^T 's genome was 52.02 mol%. Based on 16S rRNA gene sequence analysis, strain SPR ^T was distinct from previously described Deltaproteobacteria , exhibiting the closest affiliation to Desulfarculus baarsii DSM 2075 ^T and Desulfocarbo indianensis SCBM ^T , with only 91% similarity between their respective 16S gene sequences. In silico genome comparison supported the distinctiveness between strain SPR ^T and both Desulfocarbo indianensis SCBM ^T and Desulfarculus baarsii DSM 2075 ^T . Based on physiological differences, as well as phylogenetic and genomic comparisons, we propose to classify SPR ^T 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.