Diffusion of dextran through microporous membrane filters

https://doi.org/10.1016/0376-7388(94)87011-XGet rights and content

Abstract

The production of large macromolecules such as polysaccharides by microbial cells retained behind microporous membranes is subject to mass transfer limitations within the membranes. This paper describes a quantitative investigation of these diffusional limitations in commercially available microporous membrane filters using various dextran fractions as solutes. Dextran diffusivities in membrane pores were determined using a well-stirred diffusion cell. Dextran fractions were characterized by their intrinsic viscosity and weight-average molecular weight (Mw determined by light scattering. Hydrodynamic radii (rH) were estimated from the macromolecular parameters using the Mark—Houwink and Stokes—Einstein relationships. The tested membranes involved a series of mixed ester cellulose filters with pore radii (rp) ranging from 0.11 to 0.6 μm, two track-etched polycarbonate membranes and one inorganic (alumina) membrane. All macromolecules except the smallest (Mw=10,500, rH=27 Å) showed restricted diffusion in the membranes. Their effective diffusivities (Dp) were an increasing function of the membrane pore size. For any given membrane, Dp decreased as Mw increased. The diffusion data did not fit the Renkin model for a hard sphere diffusing through a cylindrical pore. These results are discussed in terms of membrane and solute characteristics.

References (30)

  • J. Tampion et al.

    Immobilized Cells: Principles and Applications

  • G.A. Junter and M. Labbé, French Pat. 2,597,498...
  • A. Planchard et al.

    Photoproduction of molecular hydrogen by Rhodospirillum rubrum immobilized in composite agar layer/microporous membrane structures

    Appl. Microbiol. Biotechnol.

    (1989)
  • D. Lemoine et al.

    Reduction of nitrate by Pseudomonas putrefaciens entrapped in composite agar layer/microporous membrane structures

    Biotechnol. Lett.

    (1988)
  • D. Lemoine et al.

    Biological denitrification of water in a two-chambered immobilized-cell bioreactor

    Appl. Microbiol. Biotechnol.

    (1991)
  • Cited by (53)

    • Hydrodynamic chromatography using flow of a highly concentrated dextran solution through a coiled tube

      2016, Carbohydrate Polymers
      Citation Excerpt :

      If the occupied volume ratio is more than one, the dextran would be interacted each other, possibly increasing the viscosity of dextran solution. Dextran (2,000,000 g/mol) at 10 g/L in water has a hydrodynamic radius of 27 nm (Lebrun & Junter, 1994). At 10 g/L of dextran (2,000,000 g/mol), the occupied dextran volume ratio is calculated to be 0.24.

    • Reversible extension and shrinkage of solvent-responsive dextran chains produced by enzymatic reaction

      2011, Journal of Membrane Science
      Citation Excerpt :

      Soluble dextran has a random coil conformation due to hydrogen bonding via multiple hydroxyl groups. The Stokes radii of dextrans with molecular masses 10 and 2000 kDa are 2.7 and 27.2 nm, respectively [22]. The conformation of dextran is changed by surrounding media.

    View all citing articles on Scopus
    View full text