CHARACTERISTICS OF SULFOBACILLUS-ACIDOPHILUS SP-NOV AND OTHER MODERATELY THERMOPHILIC MINERAL-SULFIDE-OXIDIZING BACTERIA

Several isolates of Gram-positive, acidophilic, moderately thermophili c, ferrous-iron- and mineral-sulphide-oxidizing bacteria were examined to establish unequivocally the characteristics of Sulfobacillus-like bacteria. Two species were evident: Sulfobacillus thermosulfidooxidans with 48-50 mol% G + C and Sulfobacillus acidophilus sp. nov. with 55- 57 mol% G + C. Both species grew autotrophically and mixotrophically o n ferrous iron, on elemental sulphur in the presence of yeast extract, and heterotrophically on yeast extract. Autotrophic growth on sulphur was consistently obtained only with S. acidophilus.