Sulfolobus metallicus, sp. nov., a Novel Strictly Chemolithoautotrophic Thermophilic Archaeal Species of Metal-Mobilizers

Five new isolates of archaeal coccoid thermoacidophiles were obtained from Icelandic solfataric fields. They are strict chemolithoautotrophs gaining energy by oxidation of S° and sulfidic ores. The new strains grow between 50 and 75 °C and p H 1 and 4.5 and tolerate N a C l concentrations of up to 3.0%. The G C - content of their D N A is 38 m o l % . The new isolates resemble members of Sulfolobus in their morphology, their ability to oxidize reduced sulfur compounds and their GC-content. They are different in their strictly chemolithoautotrophic mode of life, their ore-leaching capacity, D N A / D N A hybridization and incomplete serological cross-reaction of R N A polymerase. Therefore, we describe here a new species, Sulfolobus metallicus. Type strain is Sulfolobus metallicus (Kra 2 3 ; D S M 6482)

Growth by Aerobic Oxidation of Molecular Hydrogen in Archaea - a Metabolic Property so far Unknown for this Domain

Members of the genera Sulfolobus, Acidianus and Metallosphaera were found to be able to grow chemo-lithoautotrophically on H 2 / 0 2. Under these conditions, the strains grew between about 0.2 and 10 % 0 2 per vol. (opt: —1 % 0 2). The oxidation of H 2 by 0 2 was confirmed by the addition of D 2 as a tracer. To our knowledge, this is the first demonstration of H 2 oxidation by 0 2 among the Archaea

Life above the boiling point of water?

Various extremely thermophilic archaebacteria exhibit optimum growth at above 80°C. Pyrodictium is the most thermophilic of these organisms, growing at temperatures of up to U 0 ° C and exhibiting optimum growth at about 105°C. All of these organisms grow by diverse types of anaerobic and aerobic metabolism