Three-dimensional reconstruction of bioactive membranes and pore-scale simulation of enzymatic reactions: The case of lactose hydrolysis

Bali, Nadia; Petsi, A.J.; Skouras, E. D.; Burganos, Vasilis N.

doi:10.1016/j.memsci.2016.11.013

Cited by 8 publications

(7 citation statements)

References 25 publications

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“…The algorithm allowed random placement of the spheres over the working domain. The first, simple, case that was considered was that of granular media that were made up of spheres with no contact between them [26]. An example of a granular medium with porosity 0.7 is presented in Figure 3.…”

Section: Simulation Of Aggregate Formationmentioning

confidence: 99%

An Efficient Meshless Numerical Method for Heat Conduction Studies in Particle Aggregates

et al. 2020

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A new meshless numerical approach for studying heat conduction in particulate systems was developed that allows the efficient computation of the temperature distribution and the effective thermal conductivity in particle aggregates. The incorporation of the discretization-corrected particle strength exchange operator in meshless local Petrov–Galerkin calculations is suggested here, which was shown to perform better than previously tested trial functions, regarding the speed of convergence and accuracy. Moreover, an automated algorithm for node refinement was developed, which avoids the necessity for user intervention. This was quite important in the study of particle aggregates due to the appearance of multiple points of contact between particles. An alternative approach for interpolation is also presented, that increased the stability of the methods and reduced the computational cost. Test case models, commercial computational fluid dynamics software, and experimental data were used for validation. Heat transport in various aggregate morphologies was also studied using sophisticated aggregation models, in order to quantify the effect of aggregate fractal dimension on the nanofluid conductivity, targeting eventually the optimization of heat transfer applications. A trend of effective conductivity enhancement upon reduction of the fractal dimension of the aggregate was noted.

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Section: Simulation Of Aggregate Formationmentioning

confidence: 99%

An Efficient Meshless Numerical Method for Heat Conduction Studies in Particle Aggregates

et al. 2020

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“…where r c,layer is the characteristic capillary tube radius, τ layer is the layer tortuosity, K e f f ,layer is the membrane layer permeability, and ε layer is the membrane layer porosity, and subscript layer takes values 1 or 2 for the skin and the adsorptive layer, respectively. The overall effective diffusion coefficient and the effective permeability are calculated with the method of membrane layer resistances in series [26]. For a system with two different membrane layers, the overall diffusivity and permeability for radial flow is obtained using the harmonic average: Assuming bulk diffusion for all solutes in the total membrane topology and dividing Equation (25) with the bulk diffusivity of the toxin, the following equation is obtained:…”

Section: Mass Transportmentioning

confidence: 99%

Evaluation of the Toxin-to-Protein Binding Rates during Hemodialysis Using Sorbent-Loaded Mixed-Matrix Membranes

et al. 2018

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The transport and reaction phenomena that take place in multi-layered mixed-matrix membranes with activated carbon (AC) sorbents that are expected to improve extra-corporeal blood purification, are studied at the macroscopic scale. A model was developed that aims at the description of the removal efficiency of harmful uremic toxins from the blood in the presence of carbon-adsorptive particles and produces results that are aligned with the experimental data. The importance of the generally unknown kinetic rate constants of the association of toxins to albumin is investigated through sensitivity analysis. Matching with further experimental data allowed the extraction of vital kinetic rate constants for key uremic toxins such as indoxyl sulfate (IS) and p-cresyl sulfate (PCS). Moreover, the effects of the plasma composition, as well as of the membrane loading with activated carbon, on the total removal of the protein-bound toxins are quantified and discussed.

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“…Through simple dead-end filtration, enzyme molecules can be immobilized equably in the membrane pores by hydrophobic interactions, thereby improving the enzyme loading and stability relative to immobilization on the membrane surface [ 24 ]. Moreover, some researchers have tried to fix enzymes in membrane pores with homogeneous structures in order to increase the amount of enzyme loading, although the accompanying problem that the enzyme molecules are inclined to block the pores and cause membrane fouling needs to be solved [ 25 , 26 ]. By contrast, polysulfone (PSF) membranes with radial gradient pore structure (RGM-PSF) have advantages that greatly increase the number of enzyme immobilization sites and allow the fixation of enzyme molecules in the three-dimensional network structure of the membrane; this effectively reduced the aggregation of the enzyme and gave excellent performance, including high flux, low osmosis resistance, and outstanding catalytic efficiency [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Enzymes on a Phospholipid Bionically Modified Polysulfone Gradient-Pore Membrane for the Enhanced Performance of Enzymatic Membrane Bioreactors

et al. 2018

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Enzymatic membrane bioreactors (EMBRs), with synergistic catalysis-separation performance, have increasingly been used for practical applications. Generally, the membrane properties, particularly the pore structures and interface interactions, have a significant impact on the catalytic efficiency of the EMBR. Therefore, a biomimetic interface based on a phospholipid assembled onto a polysulfone hollow-fiber membrane with perfect radial gradient pores (RGM-PSF) has been prepared in this work to construct a highly efficient and stable EMBR. On account of the special pore structure of the RGM-PSF with the apertures decreasing gradually from the inner side to the outer side, the enzyme molecules could be evenly distributed on the three-dimensional skeleton of the membrane. In addition, the supported phospholipid layer in the membrane, prepared by physical adsorption, was used for the immobilization of the enzymes, which provides sufficient linkage to prevent the enzymes from leaching but also accommodates as many enzyme molecules as possible to retain high bioactivity. The properties of the EMBR were studied by using lipase from Candida rugosa for the hydrolysis of glycerol triacetate as a model. Energy-dispersive X-ray and circular dichroism spectroscopy were employed to observe the effect of lecithin on the membrane and structure changes in the enzyme, respectively. The operational conditions were investigated to optimize the performance of the EMBR by testing substrate concentrations from 0.05 to 0.25 M, membrane fluxes from 25.5 to 350.0 L·m−2·h−1, and temperatures from 15 to 55 °C. As a result, the obtained EMBR showed a desirable performance with 42% improved enzymatic activity and 78% improved catalytic efficiency relative to the unmodified membrane.

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Three-dimensional reconstruction of bioactive membranes and pore-scale simulation of enzymatic reactions: The case of lactose hydrolysis

Cited by 8 publications

References 25 publications

An Efficient Meshless Numerical Method for Heat Conduction Studies in Particle Aggregates

An Efficient Meshless Numerical Method for Heat Conduction Studies in Particle Aggregates

Evaluation of the Toxin-to-Protein Binding Rates during Hemodialysis Using Sorbent-Loaded Mixed-Matrix Membranes

Immobilization of Enzymes on a Phospholipid Bionically Modified Polysulfone Gradient-Pore Membrane for the Enhanced Performance of Enzymatic Membrane Bioreactors

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