HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Bredholt, S. Articles by Ahring, B. K. Search for Related Content PubMed Articles by Bredholt, S. Articles by Ahring, B. K. Agricola Articles by Bredholt, S. Articles by Ahring, B. K.

Caldicellulosiruptor kristjanssonii sp. nov., a cellulolytic, extremely thermophilic, anaerobic bacterium

Sylvia Bredholt^1,, Jacob Sonne-Hansen¹, Preben Nielsen², Indra M. Mathrani¹ and Birgitte K. Ahring¹

¹ Department of Biotechnology, The Technical University of Denmark, Block 113, DK-2800 Lyngby, Denmark
² Enzyme Research Novo Nordisk A/S, Novo Allé, 2880 Bagsværd, Denmark

Author for correspondence: Birgitte K. Ahring. Tel: +45 45 25 15 66. Fax: +45 45 93 28 50. e-mail: bka{at}ibt.dtu.dk

ABSTRACT

A cellulolytic anaerobic bacterium, strain I77R1B^T, was isolated from a biomat sample of an lcelandic, slightly alkaline, hot spring (78 °C). Strain I77R1B^T 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 I77R1B^T had a generation time of 2 h. During growth on Avicel, strain I77R1B^T 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 I77R1B^T 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. (I77R1B^T) is proposed.

Key Words: Caldicellulosiruptor kristjanssonii sp. nov. strain I77R1B^T • cellulolytic anaerobic bacterium • thermophile

The EMBL accession number for the 16S rRNA gene sequence of strain I77R1B^T is AJ004811.

Present address: MATFORSK, Norwegian Food Research Institute, Osloveien 1, N-1430 Ås, Norway.

This article has been cited by other articles:

				M. L. Miroshnichenko, I. V. Kublanov, N. A. Kostrikina, T. P. Tourova, T. V. Kolganova, N.-K. Birkeland, and E. A. Bonch-Osmolovskaya Caldicellulosiruptor kronotskyensis sp. nov. and Caldicellulosiruptor hydrothermalis sp. nov., two extremely thermophilic, cellulolytic, anaerobic bacteria from Kamchatka thermal springs Int J Syst Evol Microbiol, June 1, 2008; 58(6): 1492 - 1496. [Abstract] [Full Text] [PDF]

				R. U. Onyenwoke, Y.-J. Lee, S. Dabrowski, B. K. Ahring, and J. Wiegel Reclassification of Thermoanaerobium acetigenum as Caldicellulosiruptor acetigenus comb. nov. and emendation of the genus description Int J Syst Evol Microbiol, June 1, 2006; 56(6): 1391 - 1395. [Abstract] [Full Text] [PDF]