Biooxidation capacity of the extremely thermoacidophilic archaeonMetallosphaera sedula under bioenergetic challenge

Han, Chae J.; Kelly, Robert M.

doi:10.1002/(sici)1097-0290(19980620)58:6<617::aid-bit7>3.0.co;2-l

Cited by 15 publications

(6 citation statements)

References 40 publications

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“…Metallosphaera sedula is an extremely thermoacidophilic archaeon that stands out from related extremophiles by its physiological versatility (Table 1). M. sedula grows heterotrophically on peptides, autotrophically by fixing CO 2 by using H 2 as a reductant, and mixotrophically on Casamino Acids and FeSO 4 or metal sulfides (1,2,8,10,12,17). Recent studies of M. sedula's 3-hydroxypropionate/4-hydroxybutyrate cycle (4,13,19), in conjunction with the availability of genome sequence information (3), provided the basis here for examining mixotrophic growth in M. sedula more closely by using transcriptomic analysis.…”

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confidence: 99%

Physiological Versatility of the Extremely Thermoacidophilic Archaeon Metallosphaera sedula Supported by Transcriptomic Analysis of Heterotrophic, Autotrophic, and Mixotrophic Growth

Auernik

Kelly

2010

Appl Environ Microbiol

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Comparative transcriptomic analysis of autotrophic, heterotrophic, and mixotrophic growth of the archaeon Metallosphaera sedula (70°C, pH 2.0) revealed candidates for yet-to-be-confirmed components of the 3-hydroxypropionate/4-hydroxybutyrate pathway and implicated a membrane-bound hydrogenase (Msed_0944-Msed_0946) for growth on H2. Routes for generation of ATP and reducing equivalents were also identified.

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Physiological Versatility of the Extremely Thermoacidophilic Archaeon Metallosphaera sedula Supported by Transcriptomic Analysis of Heterotrophic, Autotrophic, and Mixotrophic Growth

Auernik

Kelly

2010

Appl Environ Microbiol

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“…For chalcopyrite (CuFeS 2 ) bioleaching, for example, higher temperatures can lead to faster overall leaching kinetics, in part by minimizing passivation, which slows rates at the mineral surface (15, 16). Metallosphaera sedula, an extremely thermoacidophilic, metal-mobilizing crenarchaeon growing optimally at 70 to 75°C and pH 2 (3), has been examined in this regard (7,11). Key to bioleaching capacity in this microorganism is the dissimilatory oxidation of iron and sulfur, mediated by membrane-associated electron transport chains that are anchored by terminal oxidases (2, 3, 12).…”

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Impact of Molecular Hydrogen on Chalcopyrite Bioleaching by the Extremely Thermoacidophilic Archaeon Metallosphaera sedula

Auernik

Kelly

2010

Appl Environ Microbiol

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Hydrogen served as a competitive inorganic energy source, impacting the CuFeS 2 bioleaching efficiency of the extremely thermoacidophilic archaeon Metallosphaera sedula. Open reading frames encoding key terminal oxidase and electron transport chain components were triggered by CuFeS 2 . Evidence of heterotrophic metabolism was noted after extended periods of bioleaching, presumably related to cell lysis.For bioleaching processes focused on the recovery of base, precious, and strategic metals from low-grade ores, most microorganisms studied to date are mesophilic bacteria (18). However, moderately and extremely thermoacidophilic archaea may be advantageous in certain bioleaching applications and should be considered (7, 8; T. Harvey and W. van der Merwe, presented at the Bio & Hydrometallurgy Meeting, Capetown, South Africa, 2002). For chalcopyrite (CuFeS 2 ) bioleaching, for example, higher temperatures can lead to faster overall leaching kinetics, in part by minimizing passivation, which slows rates at the mineral surface (15, 16). Metallosphaera sedula, an extremely thermoacidophilic, metal-mobilizing crenarchaeon growing optimally at 70 to 75°C and pH 2 (3), has been examined in this regard (7,11). Key to bioleaching capacity in this microorganism is the dissimilatory oxidation of iron and sulfur, mediated by membrane-associated electron transport chains that are anchored by terminal oxidases (2, 3, 12). For M. sedula, another factor that needs to be considered is the impact of inorganic energy sources, other than metal sulfides, on bioleaching. This issue was considered here by examining the influence of molecular hydrogen on M. sedula CuFeS 2 bioleaching.M. sedula (DSMZ 5348) was grown aerobically at 70°C in an orbital bath (70 rpm). Autotrophic cultures (headspace content: 7% CO 2 , 14% O 2 , 28% H 2 , balance N 2 ) were used to inoculate 1-liter bottles containing 300 ml of DSMZ medium 88 (pH 2), supplemented with 10 g/liter chalcopyrite (provided by Greg Olsen [Geosynfuels, Golden, CO]), and a headspace of either air, air plus CO 2 (7% final concentration), or the autotrophic mix mentioned above. Cells were enumerated using epifluorescence microscopy with acridine orange stain. Cultures growing exponentially were harvested 1 day postinoculation and compared to CuFeS 2 -grown cultures that were harvested 3 or 9 days postinoculation. Harvesting was done as previously described (2, 3). Methods used for microarray construction, RNA preparation, slide scanning, and data analysis were also as described previously, with the exception that Trizol (Invitrogen) was used as the RNA extraction reagent and a Packard BioChip Scanarray 4000 scanner was used for slide scanning. Significant differential transcription, or "response," was defined as relative changes of Ն2 (where a log 2 value of Ϯ1 means a 2-fold change) having significance values of Ն5.4 (Bonferroni correction equivalent to a P value of 4.0 ϫ 10 Ϫ6 for this microarray configuration). Soluble iron and its oxidation state in M. sedula cultures were tracked ...

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“…Parts of bioleaching heaps can reach temperatures of approximately 75 "C (BRIERLEY, 1999). Therefore, microorganisms such as Sulfolobus, Acidiunus, or Metullosphaeru species might have the potential for industrial applications (HAN and KELLY, 1998;LINDSTROM et al, 1993;KONI-SHI et al, 1995). In general, thermophiles have simple nutritional requirements and are often characterized by a high growth rate and fast substrate turnover.…”

Section: Leaching Under Thermophilic Conditionsmentioning

confidence: 99%

Microbial Leaching of Metals

Brandl¹

2001

Biotechnology Set

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Biooxidation capacity of the extremely thermoacidophilic archaeonMetallosphaera sedula under bioenergetic challenge

Cited by 15 publications

References 40 publications

Physiological Versatility of the Extremely Thermoacidophilic Archaeon Metallosphaera sedula Supported by Transcriptomic Analysis of Heterotrophic, Autotrophic, and Mixotrophic Growth

Physiological Versatility of the Extremely Thermoacidophilic Archaeon Metallosphaera sedula Supported by Transcriptomic Analysis of Heterotrophic, Autotrophic, and Mixotrophic Growth

Impact of Molecular Hydrogen on Chalcopyrite Bioleaching by the Extremely Thermoacidophilic Archaeon Metallosphaera sedula

Microbial Leaching of Metals

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