ARCHAEOGLOBUS-PROFUNDUS SP-NOV, REPRESENTS A NEW SPECIES WITHIN THE SULFATE-REDUCING ARCHAEBACTERIA

Eleven isolates of nonmotile coccoid hyperthermophilic archaebacteria growing at temperatures up to 90 °C were obtained from the walls of active smokers and from sediments from a deep sea hydrothermal system at Guaymas, Mexico. Similar to Archaeoglobus fulgidus, they were sulfidogens showing a blue-green fluorescence at 420 nm. Sulfate, thiosulfate and sulfite served as electron acceptors. Elemental sulfur inhibited growth. In contrast to A. fulgidus, the new isolates were obligate mixotrophs strictly requiring H2 and an organic carbon source (e. g. acetate). One of the new isolates was studied in more detail. It could be further distinguished from A. fulgidus by a 5 mol% lower GC-content of its DNA (41 mol%), a different pattern of complex lipids, and by insignificant DNA homology. On the basis of these distinguishing features, a new species, Archaeoglobus profundus is described in this paper. Type strain is A. profundus AV 18 (DSM5631). © 1990, Gustav Fischer Verlag, Stuttgart · New York. All rights reserved.