Quantitative predictive modelling of ultrafiltration processes: Colloidal science approaches

Bowen, W. Richard; Williams, Paul

doi:10.1016/j.cis.2007.04.005

Cited by 33 publications

(42 citation statements)

References 38 publications

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“…Hence, the H + concentration close to a negatively charged protein s * is the electrostatic potential at the protein surface and its relationship with the net protein charge can be described as [9]: …”

Section: Theoretical Charge and Molecular Size Determinationmentioning

confidence: 99%

“…where [H b + ] is the bulk hydrogen ion concentration and the number (n i ) and intrinsic equilibrium constants (K int ) for each titratable amino acid (i) are given in Table 1B for BSA [37] and for LF [9]. The total number of positively charged amino acid residues at very low pH, i.e., where all the available sites are protonated, is Z max = 96 for BSA and Z max = 82 for LF.…”

Section: Theoretical Charge and Molecular Size Determinationmentioning

confidence: 99%

“…The equations (B1-B3) consider a single globular protein encircled by a solution of positively charged cations and negatively charged anions. The proteins radii were estimated as 35 Å for BSA [37] and 30 Å for LF [9]. The electrostatic potential is averaged over the spherical surface on the model protein surface.…”

Section: Theoretical Charge and Molecular Size Determinationmentioning

confidence: 99%

“…The description of the protein surface properties can be performed by zeta potential and particle size measurements through electrophoretic light scattering (ELS) and dynamic light scattering (DLS) techniques, respectively. Such measurements may be made in free solution and over a wide range of ionic strength and pH [9].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Accurate determination of key surface properties that determine the efficient separation of bovine milk BSA and LF proteins

Valiño

Román

Ibáñez

et al. 2014

Separation and Purification Technology

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. KeywordsDynamic light scattering, Zeta Potential, Bovine Serum Proteins, Bioprocess Design. AbstractThe aim of this work is to accurately measure fundamental surface properties, i.e., zeta potential, isoelectric point and protein size that determine the optimal separation conditions of Bovine serum albumin and lactoferrin, two high added value food proteins whose similarity in weight makes their separation a scientific and technical challenge.

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Section: Theoretical Charge and Molecular Size Determinationmentioning

confidence: 99%

Section: Theoretical Charge and Molecular Size Determinationmentioning

confidence: 99%

Section: Theoretical Charge and Molecular Size Determinationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Accurate determination of key surface properties that determine the efficient separation of bovine milk BSA and LF proteins

Valiño

Román

Ibáñez

et al. 2014

Separation and Purification Technology

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“…For the concentration of particles strongly affected by Brownian motion, ultrafiltration (UF) has become a standard method whose major advantage is its low energy requirement. It is extensively used for the purification and concentration of a large variety of proteins [1][2][3][4][5][6][7][8][9], food stuff [10], industrial enzymes and antibody fragments [11,12], and waste water treatment [13]. UF takes place also in Bowman's capsule of the human kidneys where water and other small molecules are separated from blood [14].…”

Section: Introductionmentioning

confidence: 99%

Ultrafiltration of charge-stabilized dispersions at low salinity

et al. 2016

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We present a comprehensive study of cross-flow ultrafiltration (UF) of charge-stabilized suspensions, under low-salinity conditions of electrostatically strongly repelling colloidal particles. The axially varying permeate flux, near-membrane concentration-polarization (CP) layer and osmotic pressure profiles are calculated using a macroscopic diffusion-advection boundary layer method, and are compared with filtration experiments on aqueous suspensions of charge-stabilized silica particles. The theoretical description based on the one-component macroion fluid model (OCM) accounts for the strong influence of surface-released counterions on the renormalized colloid charge and suspension osmotic compressibility, and for the influence of the colloidal hydrodynamic interactions and electric double layer repulsion on the concentration-dependent suspension viscosity η, and collective diffusion coefficient Dc. A strong electro-hydrodynamic enhancement of Dc and η, and likewise of the osmotic pressure, is predicted theoretically, as compared with their values for a hard-sphere suspension. We also point to the failure of generalized Stokes-Einstein relations describing reciprocal relations between Dc and η. According to our filtration model, Dc is of dominant influence, giving rise to an only weakly developed CP layer having practically no effect on the permeate flux. This prediction is quantitatively confirmed by our UF measurements of the permeate flux using an aqueous suspension of charged silica spheres as the feed system. The experimentally detected fouling for the largest considered transmembrane pressure values is shown not to be due to filter cake formation by crystallization or vitrification.

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Protein Ultrafiltration

Reis¹,

Zydney²

2010

Encyclopedia of Industrial Biotechnology

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Protein ultrafiltration is a pressure‐driven membrane process used for the concentration and/or purification of protein solutions. Ultrafiltration membranes typically have mean pore size between 10 and 500 Å, which is intermediate between reverse osmosis and microfiltration. Although ultrafiltration has often been viewed as a purely size‐based separation, with species larger than the membrane pores being fully retained while smaller species pass freely, separation in ultrafiltration actually occurs because of differences in the rate of filtration of different components across the membrane in response to a given pressure driving force. Solute filtration rates, and thus the membrane selectivity, are determined by both thermodynamic (e.g. partitioning) and hydrodynamic (e.g. transport) interactions. Ultrafiltration is currently used throughout downstream processing for protein concentration, buffer exchange and desalting, protein purification, virus clearance, and clarification. Buffer exchange and desalting are typically accomplished using a diafiltration mode in which the low molecular weight components are washed away from the protein by simultaneously adding fresh buffer (or solvent) to the feed during ultrafiltration. Protein purification is accomplished using high performance tangential flow filtration, with the product collected in either the retentate or filtrate depending on the relative filtration rates. Virus filtration uses larger pore ultrafiltration membranes, which are permeable to protein but provide significant virus removal.

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Quantitative predictive modelling of ultrafiltration processes: Colloidal science approaches

Cited by 33 publications

References 38 publications

Accurate determination of key surface properties that determine the efficient separation of bovine milk BSA and LF proteins

Accurate determination of key surface properties that determine the efficient separation of bovine milk BSA and LF proteins

Ultrafiltration of charge-stabilized dispersions at low salinity

Protein Ultrafiltration

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