Enzymes of aerobic respiration on iron

Blake, Robert C.; Shute, Elizabeth A.; Greenwood, Michelle; Spencer, G.H.; Ingledew, W. John

doi:10.1111/j.1574-6976.1993.tb00261.x

Cited by 82 publications

(26 citation statements)

References 23 publications

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“…Bob Blake (Xavier University) and colleagues have investigated components of iron oxidation in at least five different acidophilic microorganisms, three bacteria ( Acidithiobacillus ferrooxidans , unidentified bacterium m1, Leptospirillum ferrooxidans ), and two archaea ( Sulfobacillus metallicus and Metallosphaera sedula ) [5,6]. In all five organisms the components of the electron transport chain were very different and the conclusion was that the ability to use ferrous iron as an electron donor has probably evolved independently at several times.…”

Section: Reviewmentioning

confidence: 99%

Characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates

Rawlings

2005

Microb Cell Fact

361

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Microorganisms are used in large-scale heap or tank aeration processes for the commercial extraction of a variety of metals from their ores or concentrates. These include copper, cobalt, gold and, in the past, uranium. The metal solubilization processes are considered to be largely chemical with the microorganisms providing the chemicals and the space (exopolysaccharide layer) where the mineral dissolution reactions occur. Temperatures at which these processes are carried out can vary from ambient to 80°C and the types of organisms present depends to a large extent on the process temperature used. Irrespective of the operation temperature, biomining microbes have several characteristics in common. One shared characteristic is their ability to produce the ferric iron and sulfuric acid required to degrade the mineral and facilitate metal recovery. Other characteristics are their ability to grow autotrophically, their acid-tolerance and their inherent metal resistance or ability to acquire metal resistance. Although the microorganisms that drive the process have the above properties in common, biomining microbes usually occur in consortia in which cross-feeding may occur such that a combination of microbes including some with heterotrophic tendencies may contribute to the efficiency of the process. The remarkable adaptability of these organisms is assisted by several of the processes being continuous-flow systems that enable the continual selection of microorganisms that are more efficient at mineral degradation. Adaptability is also assisted by the processes being open and non-sterile thereby permitting new organisms to enter. This openness allows for the possibility of new genes that improve cell fitness to be selected from the horizontal gene pool. Characteristics that biomining microorganisms have in common and examples of their remarkable adaptability are described.

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Section: Reviewmentioning

confidence: 99%

Characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates

Rawlings

2005

Microb Cell Fact

361

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“…But, from a biotechnological viewpoint and in conditions of very low pH AMD, Fe 2+ oxidation is probably more important in Ferroplasma spp., as they are the predominant iron oxidizers present at low pH and they have been found in many industrial bioleaching operations (Edwards et al, 2000). Furthermore, preliminary investigations of acidophile Fe 2+ oxidation indicate that mechanisms of other acidophiles differ from that of A. ferrooxidans (Barr et al, 1990;Blake et al, 1993;Hart et al, 1991). A putative electron transport chain for Ferroplasma Type II is suggested to contain components involved in oxidation of both organic carbon and Fe 2+ (Tyson et al, 2004).…”

Section: Introductionmentioning

confidence: 95%

Analysis of differential protein expression during growth states of Ferroplasma strains and insights into electron transport for iron oxidation

2005

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To investigate the metabolic biochemistry of iron-oxidizing extreme acidophiles, a proteomic analysis of chemomixotrophic and chemo-organotrophic growth, as well as protein expression in the absence of organic carbon, was carried out in Ferroplasma species. Electron transport chain inhibitor studies, spectrophotometric analysis and proteomic results suggest that oxidation of ferrous iron may be mediated by the blue copper-haem protein sulfocyanin and the derived electron passes to a cbb3 terminal electron acceptor. Despite previous suggestions of a putative carbon dioxide fixation pathway, no up-regulation of proteins typically associated with carbon dioxide fixation was evident during incubation in the absence of organic carbon. Although a lack of known carbon dioxide fixation proteins does not constitute proof, the results suggest that these strains are not autotrophic. Proteins putatively involved in central metabolic pathways, a probable sugar permease and flavoproteins were up-regulated during chemo-organotrophic growth in comparison to the protein complement during chemomixotrophic growth. These results reflect a higher energy demand to be derived from the organic carbon during chemo-organotrophic growth. Proteins with suggested function as central metabolic enzymes were expressed at higher levels during chemomixotrophic growth by Ferroplasma acidiphilum Y(T) compared to 'Ferroplasma acidarmanus' Fer1. This study addresses some of the biochemical and bioenergetic questions fundamental for survival of these organisms in extreme acid-leaching environments.

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“…An important exception to this, however, is Fe(II)-oxidation that occurs in microaerobic or anoxic environments as a result of the activity of microorganisms that oxidize Fe(II) to generate energy for growth. Microorganisms of this type include those that couple Fe(II)-oxidation to the reduction of nitrate at neutral pH (e.g., Benz et al, 1998;Straub and Buchholz-Cleven, 1998), or to the reduction of oxygen at either low (e.g., Blake et al, 1993;Edwards et al, 2000), or neutral pH (e.g., Emerson and Moyer, 1997), and the anaerobic Fe(II)-oxidizing phototrophs (e.g., Widdel et al, 1993;Ehrenreich and Widdel, 1994;Heising and Schink, 1998). Under oxygen-deplete conditions, microbially mediated Fe(II)-oxidation is an important component of the Fe redox cycle.…”

Section: Introductionmentioning

confidence: 99%

Iron isotope fractionation by Fe(II)-oxidizing photoautotrophic bacteria 1 1Associate editor: D. E. Canfield

Croal¹,

Johnson²,

Beard³

et al. 2004

Geochimica et Cosmochimica Acta

328

241

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Enzymes of aerobic respiration on iron

Cited by 82 publications

References 23 publications

Characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates

Characteristics and adaptability of iron- and sulfur-oxidizing microorganisms used for the recovery of metals from minerals and their concentrates

Analysis of differential protein expression during growth states of Ferroplasma strains and insights into electron transport for iron oxidation

Iron isotope fractionation by Fe(II)-oxidizing photoautotrophic bacteria 1 1Associate editor: D. E. Canfield

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