Archives of Microbiology

, Volume 128, Issue 4, pp 343-348

First online:

Thermoanaerobacter ethanolicus gen. nov., spec. nov., a new, extreme thermophilic, anaerobic bacterium

  • Jürgen WiegelAffiliated withDepartment of Biochemistry, University of Georgia
  • , Lars G. LjungdahlAffiliated withDepartment of Biochemistry, University of Georgia

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Two strains, JW 200 and JW 201, of an extreme thermophilic, non-spore-forming anaerobic bacterium were isolated from alkaline and slightly acidic hot springs located in Yellowstone National Park. Both strains were peritrichously flagellated rods. Cell size varied from 0.5–0.8 by 4–100 μm; coccoid-shaped cells of about 1 μm in diameter frequently occurred. Division was often unequal. Spheroplast-like forms were visible at the late logarithmic growth phase. The Gram reaction was variable. The DNA base composition of the two strains was between 37 and 39 mol% guanine plus cytosine as determined by buoyant density measurements and approximately 32% by the thermal denaturation method. The main fermentation products from hexoses were ethanol and CO2. Growth occurred between 37 and 78°C and from pH 4.4 to 9.8. The name Thermoanaerobacter ethanolicus gen. nov., spec. nov. was proposed for the two, new isolates. Strain JW 200 was designated as the type strain.

Key words

Isolation Extreme thermophilic anaerobic bacteria Thermoanaerobacter ethanolicus Yellowstone Natl. Park Ethanol producer