Desulfotomaculum geothermicum sp. nov., a thermophilic, fatty acid-degrading, sulfate-reducing bacterium isolated with H2 from geothermal ground water

Abstract

A strictly anaerobic, thermophilic, fatty acids-degrading, sporulating sulfate-reducing bacterium was isolated from geothermal ground water. The organism stained Gram-negative and formed gas vacuoles during sporulation. Lactate, ethanol, fructose and saturated fatty acids up to C18 served as electron donors and carbon sources with sulfate as external electron acceptor. Benzoate was not used. Stoichiometric measurements revealed a complete oxidation of part of butyrate although growth with acetate as only electron donor was not observed. The rest of butyrate was oxidized to acetate. The strain grew chemolithoautotrophically with hydrogen plus sulfate as energy source and carbon dioxide as carbon source without requirement of additional organic carbon like acetate. The strain contained a c-type cytochrome and presumably a sulfite reductase P582. Optimum temperature, pH and NaCl concentration for growth were 54 degrees C, pH 7.3-7.5 and 25 to 35 g NaCl/l. The G + C content of DNA was 50.4 mol %. Strain BSD is proposed as a new species of the spore-forming sulfate-reducing genus Desulfotomaculum, D. geothermicum.

Thermal effects on microbial composition and microbiologically induced corrosion and mineral precipitation affecting operation of a geothermal plant in a deep saline aquifer

“…were detected in fluids cooled at the heat exchanger from 75°C to 46°C. Physiological characteristics of detected SRB and Halanaerobiaceae correspond to the subsurface environment with respect to optimum temperature, salt concentration, and pH, and are commonly found in similar anaerobic saline environments such as sediments from salt lakes (Cayol et al 1994;Jakobsen et al 2006), geothermal groundwater (Daumas et al 1988), fracture water (Chivian et al 2008), as well as in oil fields and petroleum hydrocarbon contaminated sites (Magot et al 2000;Cayol et al 2002;Denger et al 2002;Bonch-Osmolovskaya et al 2003). Halophilic Desulfohalobium utahense are known moderate halophilic and mesophilic sulfate and thiosulfate reducers that use a broad range of electron donors including various short-chain fatty acids and primary (C 1-5 ) alcohols, amino acids, H 2 /acetate and H 2 /yeast extract (Jakobsen et al 2006).…”

Desulfotomaculum alcoholivorax sp. nov., a moderately thermophilic, spore-forming, sulfate-reducer isolated from a fluidized-bed reactor treating acidic metal- and sulfate-containing wastewater

“…The spores were located centrally. The cells (Fardeau et al, 1995); 5, D. gibsoniae DSM 7213 T (Kuever et al, 1999); 6, D. geothermicum DSM 3669 T (Daumas et al, 1988). All of the organisms shared the following characteristics: spore formation, spherical central or subterminal spores, sulfate (10 mM) reduction and oxidation of formate (10 mM), butyrate (10 mM), hexanoate (2 mM) and ethanol (10 mM) as electron donors.…”

“…The previously described mesophilic (optimal temperature 25-40 u C) Desulfotomaculum species are D. ruminis (Campbell & Postgate, 1965), D. acetoxidans (Widdel & Pfennig, 1977), D. sapomandens (Cord-Ruwisch & Garcia, 1985), D. aeronauticum (Hagenauer et al, 1997), D. halophilum (Tardy-Jacquenod et al, 1998) and D. gibsoniae (Kuever et al, 1999). The thermophilic (optimal temperature 50-70 u C) species are D. alkaliphilum (Pikuta et al, 2000), D. australicum (Love et al, 1993), D. carboxydivorans (Parshina et al, 2005), D. geothermicum (Daumas et al, 1988), D. kuznetsovii (Nazina et al, 1989), D. luciae (Liu et al, 1997), D. nigrificans (Werkman & Weaver, 1927;Campbell & Postgate, 1965), D. putei (Liu et al, 1997), D. solfataricum (Goorissen et al, 2003), D. thermoacetoxidans (Min & Zinder, 1990), D. thermobenzoicum with two subspecies, namely subsp. thermobenzoicum and subsp.…”

Molecular characterization of mesophilic and thermophilic sulfate reducing microbial communities in expanded granular sludge bed (EGSB) reactors

“…D. geothermicum (Daumas et al 1988) and Th. phaeum (Hattori et al 2000) can grow acetogenically on several alcohols, including ethanol, the only electron donor supplied to the TR.…”