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Stoichiometric modeling of oxidation of reduced inorganic sulfur compounds (Riscs) in Acidithiobacillus thiooxidans

Authors

  • Roberto A. Bobadilla Fazzini,

    Corresponding author
    1. BioSigma ‘S.A.’, Loteo Los Libertadores, Lote 106, Colina, Chile; telephone: 56-2-437 9030; fax: 56-2-460 0416
    • BioSigma ‘S.A.’, Loteo Los Libertadores, Lote 106, Colina, Chile; telephone: 56-2-437 9030; fax: 56-2-460 0416
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  • Maria Paz Cortés,

    1. Laboratory of Bioinformatics and Mathematics of the Genome, Center for Mathematical Modeling (UMI2807-CNRS) and FONDAP Center for Genome Regulation, Santiago, Chile
    2. Faculty of Mathematical and Physical Sciences, University of Chile, Santiago, Chile
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  • Leandro Padilla,

    1. BioSigma ‘S.A.’, Loteo Los Libertadores, Lote 106, Colina, Chile; telephone: 56-2-437 9030; fax: 56-2-460 0416
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  • Daniel Maturana,

    1. Laboratory of Bioinformatics and Mathematics of the Genome, Center for Mathematical Modeling (UMI2807-CNRS) and FONDAP Center for Genome Regulation, Santiago, Chile
    2. Faculty of Mathematical and Physical Sciences, University of Chile, Santiago, Chile
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  • Marko Budinich,

    1. Laboratory of Bioinformatics and Mathematics of the Genome, Center for Mathematical Modeling (UMI2807-CNRS) and FONDAP Center for Genome Regulation, Santiago, Chile
    2. Faculty of Mathematical and Physical Sciences, University of Chile, Santiago, Chile
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  • Alejandro Maass,

    1. Faculty of Mathematical and Physical Sciences, University of Chile, Santiago, Chile
    2. Department of Mathematical Engineering, Center for Mathematical Modeling (UMI2807-CNRS) and FONDAP Center for Genome Regulation, Santiago, Chile
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  • Pilar Parada

    Corresponding author
    1. BioSigma ‘S.A.’, Loteo Los Libertadores, Lote 106, Colina, Chile; telephone: 56-2-437 9030; fax: 56-2-460 0416
    • BioSigma ‘S.A.’, Loteo Los Libertadores, Lote 106, Colina, Chile; telephone: 56-2-437 9030; fax: 56-2-460 0416
    Search for more papers by this author

  • Conflict of interest: nothing to declare.

Abstract

The prokaryotic oxidation of reduced inorganic sulfur compounds (RISCs) is a topic of utmost importance from a biogeochemical and industrial perspective. Despite sulfur oxidizing bacterial activity is largely known, no quantitative approaches to biological RISCs oxidation have been made, gathering all the complex abiotic and enzymatic stoichiometry involved. Even though in the case of neutrophilic bacteria such as Paracoccus and Beggiatoa species the RISCs oxidation systems are well described, there is a lack of knowledge for acidophilic microorganisms. Here, we present the first experimentally validated stoichiometric model able to assess RISCs oxidation quantitatively in Acidithiobacillus thiooxidans (strain DSM 17318), the archetype of the sulfur oxidizing acidophilic chemolithoautotrophs. This model was built based on literature and genomic analysis, considering a widespread mix of formerly proposed RISCs oxidation models combined and evaluated experimentally. Thiosulfate partial oxidation by the Sox system (SoxABXYZ) was placed as central step of sulfur oxidation model, along with abiotic reactions. This model was coupled with a detailed stoichiometry of biomass production, providing accurate bacterial growth predictions. In silico deletion/inactivation highlights the role of sulfur dioxygenase as the main catalyzer and a moderate function of tetrathionate hydrolase in elemental sulfur catabolism, demonstrating that this model constitutes an advanced instrument for the optimization of At. thiooxidans biomass production with potential use in biohydrometallurgical and environmental applications. Biotechnol. Bioeng. 2013; 110: 2242–2251. © 2013 Wiley Periodicals, Inc.

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