Ferroglobus placidus DSM 10642
   
   
 


Scale: 130 pixels = 0.5 micrometer. Image by D. Rose published in: Hafenbradl, D., Keller, M., Dirmeier, R., Rachel, R., Rossnagel, P., Burggraf, S., Huber, H., and Stetter, K. O. 1996. Ferroglobus placidus gen. nov., sp. nov., a novel hyperthermophilic archaeum that oxidizes Fe2+ at neutral pH under anoxic conditions. Arch. Microbiol. 166, 308-314.

Ferroglobus placidus is an anaerobic, hyperthermophilic member of the order Archaeoglobales with a versatile metabolism. It was isolated from hydrothermally heated marine sediment It grows at neutral pH with a temperature optimum of 85?C (Hafenbradl et al., 1996). The electron acceptors it can use include nitrate and thiosulfate, while ferrous iron, hydrogen, and sulfide can serve as electron donors (Hafenbradl et al., 1996). Unlike all other known Archaeoglobales, it does not reduce sulfate. When growing on nitrate, the nitrite produced can be further reduced to N2O; therefore this is the first anaerobic denitrifier to be found (Vorholt et al., 1997). Despite the high concentration of ferrous iron generally found in hydrothermal fluids, the only thermophiles previously found to oxidize ferrous iron are members of the order Sulfolobales, and they grow poorly under these conditions. F. placidus is the first anaerobic hyperthermophile found to oxidize ferrous iron (Hafenbradl et al., 1996). F. placidus is also capable of oxidizing acetate and aromatic compounds using ferric iron as the electron acceptor (Tor et al., 2001; Tor and Lovley, 2001). It is the first archaeon and the first thermophile found to carry out the anaerobic oxidation of acetate, iron and of aromatic compounds.