- International Journal of Systematic and Evolutionary Microbiology
- Volume 49, Issue 3
f Caldicellulosiruptor kristjanssonii sp. nov., a cellulolytic, extremely thermophilic, anaerobic bacterium
- Authors: Sylvia Bredholt†, Jacob Sonne-Hansen, Preben Nielsen, Indra M. Mathrani, Birgitte K. Ahring
- Author for correspondence: Birgitte K. Ahring. Tel: +45 45 25 15 66. Fax: +45 45 93 28 50. e-mail: firstname.lastname@example.org
- First Published Online: 01 July 1999, International Journal of Systematic and Evolutionary Microbiology 49: 991-996, doi: 10.1099/00207713-49-3-991
- Subject: New Taxa - Other Bacteria
- Issue Published:
A cellulolytic anaerobic bacterium, strain I77R1BT, was isolated from a biomat sample of an lcelandic, slightly alkaline, hot spring (78 °C). Strain I77R1BT was rod-shaped, non-spore-forming, non-motile and stained Gram-negative at all stages of growth. It grew at 45–82 °C, with an optimum growth temperature around 78 °C. At 70 °C, growth occurred at pH 5·8–8·0, with an optimum near pH 7·0. At the optimum temperature and pH, with 2 g cellobiose I−1 as substrate, strain I77R1BT had a generation time of 2 h. During growth on Avicel, strain I77R1BT produced acetate, hydrogen and carbon dioxide as major fermentation products together with small amounts of lactic acid and ethanol. The strain fermented many substrates, including cellulose, xylan, starch and pectin, but did not grow with casein peptone, pyruvate, d-ribose or yeast extract and did not reduce thiosulfate to H2S. The G+C ratio of the cellular DNA was 35 mol%. Comparative 16S rDNA analysis placed strain I77R1BT among species of Caldicellulosiruptor. The closest relative was Caldicellulosiruptor lactoaceticus. Hybridization of total DNA showed 42% hybridization to C. lactoaceticus and 22% hybridization to Caldicellulosiruptor saccharolyticus. A new species, Caldicellulosiruptor kristjanssonii sp. nov. (I77R1BT) is proposed.
The EMBL accession number for the 16S rRNA gene sequence of strain I77R1BT is AJ004811.
Present address: MATFORSK, Norwegian Food Research Institute, Osloveien 1, N-1430 Ås, Norway.
- Keyword(s): cellulolytic anaerobic bacterium, thermophile, Caldicellulosiruptor kristjanssonii sp. nov. strain I77R1BT
Copyright © 1999 International Union of Microbiological Societies | Published by the Microbiology Society
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