Archives of Microbiology

, Volume 180, Issue 1, pp 60–68

Novel thermo-acidophilic bacteria isolated from geothermal sites in Yellowstone National Park: physiological and phylogenetic characteristics

  • D. Barrie Johnson
  • Naoko Okibe
  • Francisco F. Roberto
Original Paper

DOI: 10.1007/s00203-003-0562-3

Cite this article as:
Johnson, D.B., Okibe, N. & Roberto, F.F. Arch Microbiol (2003) 180: 60. doi:10.1007/s00203-003-0562-3


Moderately thermophilic acidophilic bacteria were isolated from geothermal (30–83 °C) acidic (pH 2.7–3.7) sites in Yellowstone National Park. The temperature maxima and pH minima of the isolates ranged from 50 to 65 °C, and pH 1.0–1.9. Eight of the bacteria were able to catalyze the dissimilatory oxidation of ferrous iron, and eleven could reduce ferric iron to ferrous iron in anaerobic cultures. Several of the isolates could also oxidize tetrathionate. Six of the iron-oxidizing isolates, and one obligate heterotroph, were low G+C gram-positive bacteria (Firmicutes). The former included three Sulfobacillus-like isolates (two closely related to a previously isolated Yellowstone strain, and the third to a mesophilic bacterium isolated from Montserrat), while the other three appeared to belong to a different genus. The other two iron-oxidizers were an Actinobacterium (related to Acidimicrobium ferrooxidans) and a Methylobacterium-like isolate (a genus within the α-Proteobacteria that has not previously been found to contain either iron-oxidizers or acidophiles). The other three (heterotrophic) isolates were also α-Proteobacteria and appeared be a novel thermophilic Acidisphaera sp. An ARDREA protocol was developed to discriminate between the iron-oxidizing isolates. Digestion of amplified rRNA genes with two restriction enzymes (SnaBI and BsaAI) separated these bacteria into five distinct groups; this result was confirmed by analysis of sequenced rRNA genes.


Acidophiles Biodiversity Iron oxidation Iron reduction Moderate thermophiles Yellowstone National Park 



Amplified ribosomal DNA restriction enzyme analysis


Ferrous sulfate overlay medium


Ferrous sulfate/potassium tetrathionate overlay medium


Tryptone soya broth

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • D. Barrie Johnson
    • 1
  • Naoko Okibe
    • 1
  • Francisco F. Roberto
    • 2
  1. 1.School of Biological SciencesUniversity of WalesBangorUK
  2. 2.Biotechnology DepartmentIdaho National Engineering and Environmental LaboratoryIdaho FallsUSA

Personalised recommendations