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Vitreoscilla hemoglobin expression in engineered Escherichia coli: Improved performance in high cell-density batch cultivations

Authors

  • Tania E. Pablos,

    1. Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, México, D.F.
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  • Eugenio Meza Mora,

    1. Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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  • Sylvie Le Borgne,

    1. Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, México, D.F.
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  • Octavio T. Ramírez,

    1. Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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  • Guillermo Gosset,

    1. Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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  • Dr. Alvaro R. Lara

    Corresponding author
    1. Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, México, D.F.
    • Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Artificios No. 40, Col. Miguel Hidalgo, Del. Álvaro Obregón, México DF, CP 01120, México
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Abstract

High cell-density cultivations are the preferred system for biomolecules production by Escherichia coli. It has been previously demonstrated that a strain of E. coli with a modified substrate transport system is able to attain high cell densities in batch mode, due to the very low overflow metabolism displayed. The use of elevated amounts of glucose from the beginning of the cultivation, eliminates the existence of substrate gradients due to deficient mixing at large-scale. However, the large amounts of oxygen demanded resulted in microaerobic conditions after some hours of cultivation, even at small-scale. In this work, the effect of expressing the Vitreoscilla hemoglobin (VHb) in the engineered strain during batch cultures using high-glucose concentrations was tested. Together, the expression of VHb and the modified substrate transport system resulted in a 33% increase of biomass production compared to the parental strain (W3110) lacking the VHb in batch cultivations using 25 g/L of glucose. When 50 g/L of glucose were used, expression of VHb in the modified strain led to 11% higher biomass production compared to W3110. The VHb also increased the growth rates of the strains by about 30% in the aerobic phase and more than 200% in the microaerobic phase of batch cultivation.

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