Enzyme adsorption in porous supports: Local thermodynamic equilibrium model

Pedersen, Henrik; Furler, Larry; Venκatasubramanian, Κ.; Prenosil, J. E.; Stuker, E.

doi:10.1002/bit.260270706

Cited by 44 publications

(19 citation statements)

References 16 publications

(3 reference statements)

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“…A range of 0.5 X lo-' cm2/s to 2~ 10' cm2/s for S-HyperD LS was considered, since these values are consistent with those reported by other investigators for gel-filled chromatographic media (Weaver and Carta, 1996;Voute et al, 1996). For pore diffusion, the range varied from 0.5 X lo-' cm2/s, to 7 X cm2/s, and again this range was consistent with solid-diffusion coefficients reported for porous particles (Do et al, 1982;Pedersen et al, 1985;Yoshida et al, 1994;Weaver and Carta, 1996). As in previous cases, we have investigated the effect of solid diffusion coefficients as a function of mass-transfer mechanism and degree of bed expansion.…”

Section: Aiche Journalsupporting

confidence: 74%

“…Therefore, the total protein concentration in a macroporous particle consists of both the site bound (adsorbed) and pore concentrations. Experimental batch uptake data for lysozyme adsorption by a macroporous particle like Streamline SP are well represented by a Langmuir isotherm in accordance with the following equation (Pedersen et al, 1985;Weaver and Carta, 1996;Wright et al, 1998):…”

Section: Derivation Of Model Equationsmentioning

confidence: 99%

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Modeling mass transfer and hydrodynamics in fluidized‐bed adsorption of proteins

Wright¹,

Glasser²

2001

AIChE Journal

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Section: Aiche Journalsupporting

confidence: 74%

Section: Derivation Of Model Equationsmentioning

confidence: 99%

Modeling mass transfer and hydrodynamics in fluidized‐bed adsorption of proteins

Wright¹,

Glasser²

2001

AIChE Journal

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“…In addition to operational (back pressure, aggregation, clogging) and economical (expensive) disadvantages, commonly noted diffusion limitations in these immobilized systems not only reduce the reaction rate in general but also affect the product spectrum and specifically reduce GOS formation. For example, 20-30% decreases in the GOS formation has been reported with immobilized enzymes due to introduction of mass transfer resistance in the system (28)(29)(30)(31)(32).…”

Section: Introductionmentioning

confidence: 97%

Immobilization of β‐Galactosidase on Fibrous Matrix by Polyethyleneimine for Production of Galacto‐Oligosaccharides from Lactose

Albayrak

Yang

2002

Biotechnology Progress

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The production of galacto-oligosaccharides (GOS) from lactose by Aspergillus oryzae beta-galactosidase immobilized on cotton cloth was studied. A novel method of enzyme immobilization involving PEI-enzyme aggregate formation and growth of aggregates on individual fibrils of cotton cloth leading to multilayer immobilization of the enzyme was developed. A large amount of enzyme was immobilized (250 mg/g support) with about 90-95% efficiency. A maximum GOS production of 25-26% (w/w) was achieved at near 50% lactose conversion from 400 g/L of lactose at pH 4.5 and 40 degrees C. Tri- and tetrasaccharides were the major types of GOS formed, accounting for about 70% and 25% of the total GOS produced in the reactions, respectively. Temperature and pH affected not only the reaction rate but also GOS yield to some extend. A reaction pH of 6.0 increased GOS yield by as much as 10% compared with that of pH 4.5 while decreased the reaction rate of immobilized enzyme. The cotton cloth as the support matrix for enzyme immobilization did not affect the GOS formation characteristics of the enzyme under the same reaction conditions, suggesting diffusion limitation was negligible in the packed bed reactor and the enzyme carrier. Increase in the thermal stability of PEI-immobilized enzyme was also observed. The half-life for the immobilized enzyme on cotton cloth was close to 1 year at 40 degrees C and 21 days at 50 degrees C. Stable, continuous operation in a plug-flow reactor was demonstrated for about 3 days without any apparent problem. A maximum GOS production of 26% (w/w) of total sugars was attained at 50% lactose conversion with a feed containing 400 g/L of lactose at pH 4.5 and 40 degrees C. The corresponding reactor productivity was 6 kg/L/h, which is several-hundred-fold higher than those previously reported.

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“…The initial and boundary conditions are as follows:

IC : c |_{t = 0} = c_{0}

c_{p} |_{t = 0} = 0

BC 1 : \frac{\partial c_{p}}{\partial r} |_{r = 0} = 0

BC 2 : \frac{\partial c_{p}}{\partial r} |_{r = r_{p}} = \frac{k_{f}}{D_{e}^{'}} (c - c_{p} |_{r = r_{p}})

k f can be estimated as follows :

k_{f} = \frac{2 D_{AB}}{d_{p}} + 0.31 {((), \frac{μ}{ρ D_{AB}})}^{- \frac{2}{3}} {((), \frac{Δ ρ μ g}{ρ^{2}})}^{\frac{1}{3}}

where d p is particle diameter (m), μ is the viscosity of liquid phase (Pa s), ρ is the density of liquid phase (kg/m 3 ). Δ ρ is the density difference between the adsorbent and the liquid phase (kg/m 3 ).…”

Section: Methodsmentioning

confidence: 99%

Effects of ligand density and pore size on the adsorption of bovine IgG with DEAE ion‐exchange resins

Lin

Zhu³

et al. 2012

J of Separation Science

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Immunoglobulin G is an important plasma protein with many applications in therapeutics and diagnostics, which can be purified effectively by ion exchange chromatography. The ligand densities and pore properties of ion-exchange resins have significant effects on the separation behaviors of protein, however, the understandings are quite limited. In this work, with bovine immunoglobulin as the model IgG, the adsorption isotherms and adsorption kinetics were investigated systematically with series of diethylaminoethyl ion-exchange resins with different ligand densities and pore sizes. The Langmuir equation and pore diffusion model were used to fit the experimental data. The influences of ligand density and pore size on the saturated adsorption capacity, the dissociation constant and the effective diffusivity were discussed. The adsorption capacities increased with the increase of ligand density and the decrease of pore size, and an integrative parameter was proposed to describe the combined effects of ligand density and pore size. It was also found that the effective pore diffusion coefficient of the adsorption kinetics was influenced by pore sizes of resins, but was relatively independent on the ligand densities of resins. For a given protein, the ligand density and pore size should be optimized for improving the protein adsorption.

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Enzyme adsorption in porous supports: Local thermodynamic equilibrium model

Cited by 44 publications

References 16 publications

Modeling mass transfer and hydrodynamics in fluidized‐bed adsorption of proteins

Modeling mass transfer and hydrodynamics in fluidized‐bed adsorption of proteins

Immobilization of β‐Galactosidase on Fibrous Matrix by Polyethyleneimine for Production of Galacto‐Oligosaccharides from Lactose

Effects of ligand density and pore size on the adsorption of bovine IgG with DEAE ion‐exchange resins

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