Thiopseudomonas denitrificans gen. nov., sp. nov., isolated from anaerobic activated sludge.

A Gram-staining-negative, rod-shaped, motile and facultatively anaerobic bacterial strain, designated X2T, was isolated from the sludge of an anaerobic, denitrifying, sulfide-removal bioreactor, and found to oxidize sulfide anaerobically with nitrate as electron acceptor. The strain grew at salinities of 0–3 % (w/v) NaCl (optimum, 0–1 %). Growth occurred at pH 6.0–10.0 (optimum, pH 8.0) and 10–37 °C (optimum, 30 °C). The genomic DNA G+C content was 59 mol%. Q-8 and Q-9 were detected as the respiratory quinones. The major fatty acids (>10 %) were C16 : 1ω7c and/or C16 : 1ω6c, C18 : 1ω7c and C16 : 0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and one unidentified phospholipid. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain X2T formed a novel clade within the family Pseudomonadaceae , with the highest sequence similarity to Pseudomonas caeni KCTC 22292T (93.5 %). On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics, it is proposed that this strain represents novel genus and species within the family Pseudomonadaceae , for which the name Thiopseudomonas denitrificans gen. nov., sp. nov. is proposed. The type strain is X2T ( = CCTCC M 2013362T = DSM 28679T = KCTC 42076T).