Archaeoglobus fulgidus and Thermotoga elfii, Thermophilic Isolates from Deep Geothermal Water of the Paris Basin
Abstract:Thermophilic anaerobic microorganisms with the ability to reduce sulfur compounds (e.g., sulfate and/or thiosulfate) were isolated from water samples collected from about 2000 meters depth at in situ temperatures of 70°C in a geothermal well from the Paris Basin (France). Chemical and isotopic analyses show that microbial sulfate reduction occurred in the samples. Two strains were characterized by both DNA/DNA hybridization and 16S rRNA gene sequence analysis, which indicated that they are most closely related to Thermotoga elfii, a thiosulfate-reducing bacterium, and Archaeoglobus fulgidus, a sulfate- and thiosulfate-reducing archaeon. Besides thiosulfate reduction using H2 as energy source, both isolates are shown to be able to retrieve energy from H2/Fe(III), a metabolic capability of importance in a deep biosphere context. It is suggested that T. elfii and A. fulgidus could be used, either as pure culture or as a consortium, in future laboratory studies aiming at better understanding microbial iron (III) and sulfate/thiosulfate reduction, hydrogen production/consumption, as well as the effect of microorganisms on the evolution of CO2 in deep aquifers. The present work examines numerous culture conditions and demonstrates that in spite of similarities in phylogenetic/genetic characteristics and in growth conditions, there are significant phenotypic differences between the isolated archaeal strain and the type strain of A. fulgidus. These differences, evidenced by a proteomic study, should be taken into account and could be useful parameters to be studied in the deep aquifers by geomicrobiological laboratories.
Document Type: Research Article
Affiliations: 1: Laboratoire de Microbiologie IRD, IFR-BAIM, Universites de Provence et de la Mediterranee, Marseille, CEDEX 09, France 2: Institut de Biologie Structurale et de Microbiologie, Unite de Bioenergetique et Ingenierie des Proteines (BIP), CNRS, Marseille, CEDEX 20, France 3: BRGM, Environment and Process Division, Orleans, CEDEX 2, France 4: Laboratoire de Mineralogie, IMPMC and IPGP, CNRS, Universites de Paris 6, Paris, France
Publication date: March 1, 2009