The Microbiology of Extremely Acidic Environments

Johnson, D. Barrie; Aguilera, Ángeles

doi:10.1128/9781555818821.ch4.3.1

Cited by 17 publications

(24 citation statements)

References 168 publications

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“…Other species of acidophilic bacteria (e.g. Leptospirillum ferrooxidans, Ferrimicrobium acidiphilum, Acidimicrobium ferrooxidans, Acidithrix ferrooxidans and "Ferrovum myxofaciens") catalyse the dissimilatory oxidation of ferrous iron but not sulfur [1] as was the case with the six strains of "A. ferrooxidans".…”

Section: Discussionmentioning

confidence: 90%

“…All of the isolates also catalysed the dissimilatory reduction of ferric iron under anoxic conditions though, as noted, this was limited in the case of the two Group IB strains, and it was not ascertained whether the bacteria could grow by ferric iron respiration. Ferrous iron is a widely used electron donor among acidophilic prokaryotes, due to it often being present in large concentrations in low pH environments, and also chemically stable at pH < 3 [1]. The ability to oxidize ferrous iron does not necessarily imply that microorganisms are able to conserve the energy from this reaction.…”

Section: Discussionmentioning

confidence: 99%

“…benefaciens, and Sb. sibiricus) [1], as well as Alicyclobacillus tolerans and Alb. aeris [30] can oxidize both ferrous iron and reduced sulfur.…”

Section: Discussionmentioning

confidence: 99%

“…Acidophilic microorganisms comprise a large variety of different species that are widely distributed in all three domains of known life-forms [1]. While the greatest number (and earliest isolates) of known extremely acidophilic bacteria are members of the phylum Proteobacteria, other phyla, including the Firmicutes, Nitrospirae, Actinobacteria and Aquificae, all include species that grow optimally at pH <3.…”

Section: Introductionmentioning

confidence: 99%

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Isolation and characterisation of mineral-oxidising “Acidibacillus” spp. from mine sites and geothermal environments in different global locations

Holanda

Hedrich

Nancucheo

et al. 2016

Research in Microbiology

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Eight strains of acidophilic bacteria, isolated from mine-impacted and geothermal sites from different parts of the world, were shown to form a distinct clade (proposed genus "Acidibacillus") within the phylum Firmicutes, well separated from the acidophilic genera Sulfobacillus and Alicyclobacillus. Two of the strains (both isolated from sites in Yellowstone National Park, USA) were moderate thermophiles that oxidised both ferrous iron and elemental sulphur, while the other six were mesophiles that also oxidised ferrous iron, but not sulphur. All eight isolates reduced ferric iron to varying degrees. The two groups shared <95% similarity of their 16S rRNA genes and were therefore considered to be distinct species: "Acidibacillus sulfuroxidans" (moderately thermophilic isolates) and "Acidibacillus ferrooxidans" (mesophilic isolates). Both species were obligate heterotrophs; none of the eight strains grew in the absence of organic carbon. "Acidibacillus" spp. were generally highly tolerant of elevated concentrations of cationic transition metals, though "A. sulfuroxidans" strains were more sensitive to some (e.g. nickel and zinc) than those of "A. ferrooxidans". Initial annotation of the genomes of two strains of "A. ferrooxidans" revealed the presence of genes (cbbL) involved in the RuBisCO pathway for CO2 assimilation and iron oxidation (rus), though with relatively low sequence identities.

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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

“…benefaciens, and Sb. sibiricus) [1], as well as Alicyclobacillus tolerans and Alb. aeris [30] can oxidize both ferrous iron and reduced sulfur.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Isolation and characterisation of mineral-oxidising “Acidibacillus” spp. from mine sites and geothermal environments in different global locations

Holanda

Hedrich

Nancucheo

et al. 2016

Research in Microbiology

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“…Acidophilic prokaryotes, defined as those that grow optimally at or below pH 3.0, display a far greater propensity for chemolithotrophy than other groups of bacteria and archaea that have higher pH growth optima ( Johnson and Aguilera, 2015 ; Dopson, 2016 ). This is due to a number of factors, the most important of which is that their natural habitats are often rich in reduced sulfur and iron, and sulfide minerals, but often contain relatively small concentrations of dissolved organic carbon.…”

Section: Introductionmentioning

confidence: 99%

Indirect Redox Transformations of Iron, Copper, and Chromium Catalyzed by Extremely Acidophilic Bacteria

2017

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Experiments were carried out to examine redox transformations of copper and chromium by acidophilic bacteria (Acidithiobacillus, Leptospirillum, and Acidiphilium), and also of iron (III) reduction by Acidithiobacillus spp. under aerobic conditions. Reduction of iron (III) was found with all five species of Acidithiobacillus tested, grown aerobically on elemental sulfur. Cultures maintained at pH 1.0 for protracted periods displayed increasing propensity for aerobic iron (III) reduction, which was observed with cell-free culture liquors as well as those containing bacteria. At. caldus grown on hydrogen also reduced iron (III) under aerobic conditions, confirming that the unknown metabolite(s) responsible for iron (III) reduction were not (exclusively) sulfur intermediates. Reduction of copper (II) by aerobic cultures of sulfur-grown Acidithiobacillus spp. showed similar trends to iron (III) reduction in being more pronounced as culture pH declined, and occurring in both the presence and absence of cells. Cultures of Acidithiobacillus grown anaerobically on hydrogen only reduced copper (II) when iron (III) (which was also reduced) was also included; identical results were found with Acidiphilium cryptum grown micro-aerobically on glucose. Harvested biomass of hydrogen-grown At. ferridurans oxidized iron (II) but not copper (I), and copper (I) was only oxidized by growing cultures of Acidithiobacillus spp. when iron (II) was also included. The data confirmed that oxidation and reduction of copper were both mediated by acidophilic bacteria indirectly, via iron (II) and iron (III). No oxidation of chromium (III) by acidophilic bacteria was observed even when, in the case of Leptospirillum spp., the redox potential of oxidized cultures exceeded +900 mV. Cultures of At. ferridurans and A. cryptum reduced chromium (VI), though only when iron (III) was also present, confirming an indirect mechanism and contradicting an earlier report of direct chromium reduction by A. cryptum. Measurements of redox potentials of iron, copper and chromium couples in acidic, sulfate-containing liquors showed that these differed from situations where metals are not complexed by inorganic ligands, and supported the current observations of indirect copper oxido-reduction and chromium reduction mediated by acidophilic bacteria. The implications of these results for both industrial applications of acidophiles and for exobiology are discussed.

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Bauxite Residue Neutralization Potential Using Biogenic Sulfuric and Citric Acids

Silva

Holanda

Carmo

et al. 2021

The Minerals, Metals &Amp; Materials Series

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The Microbiology of Extremely Acidic Environments

Cited by 17 publications

References 168 publications

Isolation and characterisation of mineral-oxidising “Acidibacillus” spp. from mine sites and geothermal environments in different global locations

Isolation and characterisation of mineral-oxidising “Acidibacillus” spp. from mine sites and geothermal environments in different global locations

Indirect Redox Transformations of Iron, Copper, and Chromium Catalyzed by Extremely Acidophilic Bacteria

Bauxite Residue Neutralization Potential Using Biogenic Sulfuric and Citric Acids

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