Effect of chloride on ferrous iron oxidation by a <i>Leptospirillum ferriphilum</i>‐dominated chemostat culture

Gahan, Chandra Sekhar; Sundkvist, Jan-Eric; Dopson, Mark; Sandström, Åke

doi:10.1002/bit.22709

Cited by 44 publications

(20 citation statements)

References 49 publications

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“…This value is the biomass Yield coefficient per carbon, Ycx529 GDW mole2C À Á . Considering a specific growth rate of 0.081 (1/h), 31 the specific carbon uptake rate was calculated with the equation:…”

Section: Synthesis Of Macromoleculesmentioning

confidence: 99%

Stoichiometric model and flux balance analysis for a mixed culture of Leptospirillum ferriphilum and Ferroplasma acidiphilum

Merino

Andrews

Asenjo

2014

Biotechnology Progress

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The oxidation process of sulfide minerals in natural environments is achieved by microbial communities from the Archaea and Bacteria domains. A metabolic reconstruction of two dominant species, Leptospirillum ferriphilum and Ferroplasma acidiphilum, which are always found together as a mixed culture in this natural environments, was made. The metabolic model, composed of 152 internal reactions and 29 transport reactions, describes the main interactions between these species, assuming that both use ferrous iron as energy source, and F. acidiphilum takes advantage of the organic compounds secreted by L. ferriphilum for chemomixotrophic growth. A first metabolic model for a mixed culture used in bacterial leaching is proposed in this article, which pretends to represent the characteristics of the mixed culture in a simplified manner. It was evaluated with experimental data through flux balance analysis (FBA) using as objective function the maximization of biomass. The growth yields on ferrous iron obtained for each microorganism are consistent with experimental data, and the flux distribution obtained allows understanding of the metabolic capabilities of both microorganisms growing together in a bioleaching process. The model was used to simulate the growth of F. acidiphilum on different substrates, to determine in silico which compounds maximize cell growth, and which are essential. Knockout simulations were carried out for L. ferriphilum and F. acidiphilum metabolic models, predicting key enzymes of central metabolism. The results of this analysis are consistent with experimental data from literature, showing a robust behavior of the metabolic model.

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Section: Synthesis Of Macromoleculesmentioning

confidence: 99%

Stoichiometric model and flux balance analysis for a mixed culture of Leptospirillum ferriphilum and Ferroplasma acidiphilum

Merino

Andrews

Asenjo

2014

Biotechnology Progress

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“…Osmotic stress occurs when the soluble extracellular salts differ from the concentration within the cell that either leads to cellular dehydration or lysis (Zammit and Watkin, 2016). Typical acidophile biomining strains are highly sensitive to anions and in particular chloride that have been demonstrated to inhibit ferrous iron oxidation by a Leptospirillum ferriphilum -dominated culture (Gahan et al, 2010) and the bioleaching ability of an undefined mixed acidophile consortium (Shiers et al, 2005). One exception is the salt tolerant industrial isolate, L. ferriphilum Sp-Cl and its genome sequence will aid in discovering adaptations to high salt concentrations in acidophiles (Issotta et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Multiple Osmotic Stress Responses in Acidihalobacter prosperus Result in Tolerance to Chloride Ions

et al. 2017

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Extremely acidophilic microorganisms (pH optima for growth of ≤3) are utilized for the extraction of metals from sulfide minerals in the industrial biotechnology of “biomining.” A long term goal for biomining has been development of microbial consortia able to withstand increased chloride concentrations for use in regions where freshwater is scarce. However, when challenged by elevated salt, acidophiles experience both osmotic stress and an acidification of the cytoplasm due to a collapse of the inside positive membrane potential, leading to an influx of protons. In this study, we tested the ability of the halotolerant acidophile Acidihalobacter prosperus to grow and catalyze sulfide mineral dissolution in elevated concentrations of salt and identified chloride tolerance mechanisms in Ac. prosperus as well as the chloride susceptible species, Acidithiobacillus ferrooxidans. Ac. prosperus had optimum iron oxidation at 20 g L−1 NaCl while At. ferrooxidans iron oxidation was inhibited in the presence of 6 g L−1 NaCl. The tolerance to chloride in Ac. prosperus was consistent with electron microscopy, determination of cell viability, and bioleaching capability. The Ac. prosperus proteomic response to elevated chloride concentrations included the production of osmotic stress regulators that potentially induced production of the compatible solute, ectoine uptake protein, and increased iron oxidation resulting in heightened electron flow to drive proton export by the F0F1 ATPase. In contrast, At. ferrooxidans responded to low levels of Cl− with a generalized stress response, decreased iron oxidation, and an increase in central carbon metabolism. One potential adaptation to high chloride in the Ac. prosperus Rus protein involved in ferrous iron oxidation was an increase in the negativity of the surface potential of Rus Form I (and Form II) that could help explain how it can be active under elevated chloride concentrations. These data have been used to create a model of chloride tolerance in the salt tolerant and susceptible species Ac. prosperus and At. ferrooxidans, respectively.

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“…These may lead to a slower growth of leaching microbes and a lower oxidation activity (Dopson et al, 2008;Gahan et al, 2010;Harahuc et al, 2000;Rivadeneira, 2011;Sundkvist et al, 2005). Metal accumulation into an irrigation solution may also reach inhibiting level (Rivadeneira, 2011).…”

Section: Main Variables In Bioleaching Processmentioning

confidence: 94%

The application of principal component analysis for bioheapleaching process - Case study: Talvivaara mine

Ollakka

Ruuska

Taskila

2016

Minerals Engineering

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Effect of chloride on ferrous iron oxidation by a Leptospirillum ferriphilum‐dominated chemostat culture

Cited by 44 publications

References 49 publications

Stoichiometric model and flux balance analysis for a mixed culture of Leptospirillum ferriphilum and Ferroplasma acidiphilum

Stoichiometric model and flux balance analysis for a mixed culture of Leptospirillum ferriphilum and Ferroplasma acidiphilum

Multiple Osmotic Stress Responses in Acidihalobacter prosperus Result in Tolerance to Chloride Ions

The application of principal component analysis for bioheapleaching process - Case study: Talvivaara mine

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