Thioalbus denitrificans gen. nov., sp. nov., a chemolithoautotrophic sulfur-oxidizing gammaproteobacterium, isolated from marine sediment.

A mesophilic, facultatively anaerobic, autotrophic bacterium, designated strain Su4(T), was isolated from marine sediment. The isolate was able to utilize reduced sulfur compounds including thiosulfate, tetrathionate, sulfur and sulfide but not sulfite as the energy source. Growth occurred under aerobic and denitrifying chemolithoautotrophic conditions in the presence of thiosulfate as an electron donor and bicarbonate as a carbon source. The G+C content of the genomic DNA was 64.5 mol%. Comparative 16S rRNA gene sequence studies showed that strain Su4(T) was clearly affiliated with the class Gammaproteobacteria. The isolate was Gram-negative-staining and rod-shaped, lacked flagella and grew in artificial seawater medium at 10-40 °C (optimum 28-32 °C) and in 1-5 % (w/v) NaCl (optimum 3 % NaCl). Strain Su4(T) possessed C₁₆:₀, C₁₆:₁ω7c/iso-C₁₅:₀ 2-OH and C₁₈:₁ω7c/ω9t/ω12t as the major fatty acids. On the basis of phenotypic and phylogenetic analysis, the isolate represents a novel species of a novel genus, for which the name Thioalbus denitrificans is proposed. The type strain is Su4(T) ( = KCTC 5699(T)  = JCM 15568(T)).