The first evidence of anaerobic CO oxidation coupled with H2 production by a hyperthermophilic archaeon isolated from a deep-sea hydrothermal vent

From 24 samples of hydrothermal venting structures collected at the East Pacific Rise (13degreesN), 13 enrichments of coccoid cells were obtained which grew on CO, producing H-2 and CO2 at 80degreesC. A hyperthermophilic archaeon capable of lithotrophic growth on CO coupled with equimolar production of H-2 was isolated. Based on its 16S rRNA sequence analysis, this organism was affiliated with the genus Thermococcus. Other strains of Thermococcales species (Pyrococcus furiosus, Thermococcus peptonophilus, T. profundus, T. chitonophagus, T. stetteri, T. gorgonarius, T. litoralis, and T. pacificus) were shown to be unable to grow on CO. Searches in sequence databases failed to reveal deposited sequences of genes related to CO metabolism in Thermococcales. Our work provides the first evidence of anaerobic CO oxidation coupled with H-2 production performed by an archaeon as well as the first documented case of lithotrophic growth of a Thermococcales representative.