DESULFURELLA MULTIPOTENS SP-NOV, A NEW SULFUR-RESPIRING THERMOPHILIC EUBACTERIUM FROM RAOUL ISLAND (KERMADEC ARCHIPELAGO, NEW-ZEALAND)

A new moderately thermophilic sulfur-redu cing eubacterium was isolated from bottom deposits of Green Lake (Raoul Island, Kermadec archipelago, New Zealand). Cells are short rods, 1.5-1.8 by 0.5-0.7 mu m, single or in pairs, motile with one polar flagellum, gram-negative with S-layer of subunit structure. Growth occurred between 42 and 77 degrees C with the optimum at 58-60 degrees C and at pH from 6.0 to 7.2 with the optimum at 6.4-6.8. The bacterium was obligately anaerobic and obligately sulfur-respiring, and capable of lithoautotrophic growth on a mineral medium with S degrees and H-2/CO2 gas phase. In addition to molecular hydrogen, a wide range of substrates can be utilized as energy source in the presence of elemental sulfur: pyruvate, acetate, butyrate, pentadecanate, palmitate, stearate. Products are CO2 and H2S. The G + C content of DNA is 33.5 mol%. DNA-DNA homology with the type species of the genus Desulfurella - Desulfurella acertivorans - is 69 +/- 2%. A new species, Desulfurella multipotens sp. nov., with the type strain RH-8 is described.