ABSTRACT
A new alkaliphilic, sulfate-reducing bacterium, strain Z-7935T (T = type strain), was isolated from a soda-depositing lake, Lake Magadi in Kenya. This organism is a motile vibrio which utilizes only hydrogen and formate as electron donors and sulfate, sulfite, and thiosulfate, but not sulfur, as electron acceptors. Thiosulfate is dismutated. Strain Z-7935T is an obligately sodium-dependent alkaliphile which grows in sodium carbonate medium and does not grow at pH 7; the maximum pH for growth is more than pH 10, and the optimum pH is 9.5 to 9.7. The optimum NaCl concentration for growth is 3% (wt/vol). The optimum temperature for growth is 37 degrees C. The G + C content of the DNA is 48.6 mol%. 16S ribosomal DNA sequence analysis revealed that strain Z-7935T represents a new lineage with genus status in the delta subclass of the Proteobacteria. The name Desulfonatronovibrio hydrogenovorans gen. nov., sp. nov. is proposed for this organism; the type strain of D. hydrogenovorans is strain Z-7935 (= DSM 9292).
