THERMOCOCCUS ACIDAMINOVORANS SP. NOV., A NEW HYPERTHERMOPHILIC ALKALOPHILIC ARCHAEON GROWING ON AMINO-ACIDS

From a shallow marine hydrothermal system at Vulcano (Italy), a new hy perthermophilic member of the Archaea was isolated. The cells are cocc oid - shaped and possess up to five flagella. They grow between 56 deg rees and 93 degrees C (optimum 85 degrees C) and pH 5.0-9.5 (optimum 9 .0). The organism is strictly anaerobic and grows heterotrophically on defined amino acids and complex organic substrates such as casamino a cids, yeast extract, peptone, meat extract, tryptone, and casein. Poly sulfide and elemental sulfur are reduced to H2S. In the absence of pol ysulfide or elemental sulfur, the isolate grows at a significantly red uced rate. Growth is not influenced by the presence of H-2. DNA-DNA hy bridization and 16S rRNA partial sequences indicated that the new isol ate belongs to the genus Thermococcus, and represents a new species, T hermococcus acidaminovorans. The type strain is isolate AEDII10 (DSM 1 1906).