Direct Extraction of Propionic Acid from Propionibacterium acidipropionici Broths with Tri-n-octylamine

Authors

  • A.-I. Galaction,

    1. Faculty of Medical Bioengineering, Department of Biotechnologies, “Gr. T. Popa” University of Medicine and Pharmacy, Iasi, Romania
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  • A. Carlescu,

    1. Faculty of Chemical Engineering and Environmental Protection, Department of Biochemical Engineering, “Gheorghe Asachi” Technical University, Iasi, Romania
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  • M. Turnea,

    1. Faculty of Medical Bioengineering, Department of Biotechnologies, “Gr. T. Popa” University of Medicine and Pharmacy, Iasi, Romania
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  • D. Caşcaval

    Corresponding author
    1. Faculty of Chemical Engineering and Environmental Protection, Department of Biochemical Engineering, “Gheorghe Asachi” Technical University, Iasi, Romania
    • Faculty of Chemical Engineering and Environmental Protection, Department of Biochemical Engineering, “Gheorghe Asachi” Technical University, Iasi, Romania
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Abstract

The direct reactive extraction of propionic acid from Propionibacterium acidipropionici broths with solutions of tri-n-octylamine in dichloromethane, n-butyl acetate or n-heptane underlined the strong negative influence of the cells, due to the blockage of the interface by their adsorption. The magnitude of this effect <#>depends on the affinity of the cells for the organic phase, which is more important for n-heptane, but only at biomass concentrations below 18 g L–1 d.w. (dry weight). Moreover, the interfacial mass transfer of the acid is also controlled by the solvent polarity, and is accelerated from n-heptane to dichloromethane and by the addition to the organic phase of 1-octanol as a phase modifier. The influences of the biomass concentration, the rotation speed and the solvent dielectric constant were included in a mathematical model describing the solute mass flow from the aqueous to the organic phase.

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