Isolation and Characterization of a Thermophilic, Sulfate Reducing Archaebacterium, Archaeoglobus fulgidus Strain Z

Summary An extremely thermophilic, strictly anaerobic sulfate reducing bacterium, strain Z, was isolated from sediments of a hydrothermal vent located near Mount Vulcanello, Vulcano, Italy. On the basis of 16S rRNA cataloguing, strain Z was shown to belong to the archaebacterial kingdom, representing another strain of Archaeoglobus fulgidus . The weakly motile, irregular coccoid cells showed the fluorescence regarded as typical for methanogens, when viewed under the fluorescence microscope, although no relationship with methanogens was seen from comparative analysis of antigenic fingerprints with antibody S-probes. Furthermore, methane was not produced in significant amounts. Dissimilatory sulfate reduction was found with lactate, pyruvate and 2,3-butandiol as substrates. With thiosulfate as electron acceptor H 2 /CO 2 , formate, lactate, pyruvate or fumarate were utilized as electron donors. Sulfur bloom was not used as electron acceptor. Growth was inhibited by molybdate, a typical inhibitor of sulfate reducers. Lactate was decarboxylated to acetate and part of the acetate was oxidized to CO 2 with the reducing equivalents serving for sulfate reduction. The cell envelope consisted of a hexagonally arranged S-layer. The apparent molecular weight of its subunits, staining PAS-positive, was 132000. No significant amounts of polyamines were detected. The DNA polymerase was sensitive towards aphidicolin, a specific inhibitor of DNA polymerases type a of eucaryotes and of the DNA polymerase of Methanococcus vannielii . The DNA base composition was 45 mol% G+C. Archaeoglobus fulgidus strain Z has been deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH under number DSM 4139.