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-degrees and sulfidic ores. The new strains grow between 50 and 75-degrees-C and pH 1 and 4.5 and tolerate NaCl concentrations of up to 3.0%. The GC-content of their DNA is 38 mol%. 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, DNA/DNA hybridization and incomplete serological cross-reaction of RNA polymerase. Therefore, we describe here a new species, Sulfolobus metallicus. Type strain is Sulfolobus metallicus (Kra 23; DSM 6482).