Mass transfer in heterogeneous system enzyme-substrate; Approximate analytical model for the case of liquid substrate-immobilized enzyme

1982 ◽  
Vol 47 (11) ◽  
pp. 3013-3018
Author(s):  
František Kaštánek ◽  
Jindřich Zahradník ◽  
Germanico Ocampo
Keyword(s):  
Mass Transfer ◽  
Heterogeneous System ◽  
Immobilized Enzyme ◽  
Enzymatic Reaction ◽  
Analytical Form ◽  
Approximate Model ◽  
Basic Type ◽  
Reaction Interface ◽  
Enzyme Substrate ◽  
Flow Intensity

Calculation procedure is suggested for flow intensity of substrate toward reaction interface of immobilized enzyme at simultaneous effect of enzymatic reaction and internal diffusion. The approximate model is presented in an analytical form for the basic type of Michaelis-Menten kinetics and for the case of inhibition in excess of substrate.

Mass transfer in heterogeneous system enzyme-substrate; Kinetic model of enzymatic reaction in system of two immiscible liquids

1982 ◽  
Vol 47 (11) ◽  
pp. 3019-3026 ◽  
Author(s):  
František Kaštánek ◽  
Jindřich Zahradník ◽  
Germanico Ocampo
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Kinetic Model ◽  
Interphase Boundary ◽  
Heterogeneous System ◽  
Enzymatic Reaction ◽  
Reaction Rates ◽  
Immiscible Liquids ◽  
Enzyme Substrate

Mathematical model is proposed enabling calculation of enzymatic reaction rates occuring in one phase of a system of two immiscible liquids under conditions of substrate and product transfer over the interphase boundary.

scholarly journals Trace element catalyses mineral replacement reactions and facilitates ore formation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanlu Xing ◽  
Joël Brugger ◽  
Barbara Etschmann ◽  
Andrew G. Tomkins ◽  
Andrew J. Frierdich ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Trace Elements ◽  
Fluid Flow ◽  
Large Scale ◽  
Metal Accumulation ◽  
Nucleation And Growth ◽  
Reaction Interface ◽  
Ore Formation ◽  
Key Factor ◽  
Mineral Replacement

AbstractReaction-induced porosity is a key factor enabling protracted fluid-rock interactions in the Earth’s crust, promoting large-scale mineralogical changes during diagenesis, metamorphism, and ore formation. Here, we show experimentally that the presence of trace amounts of dissolved cerium increases the porosity of hematite (Fe2O3) formed via fluid-induced, redox-independent replacement of magnetite (Fe3O4), thereby increasing the efficiency of coupled magnetite replacement, fluid flow, and element mass transfer. Cerium acts as a catalyst affecting the nucleation and growth of hematite by modifying the Fe2+(aq)/Fe3+(aq) ratio at the reaction interface. Our results demonstrate that trace elements can enhance fluid-mediated mineral replacement reactions, ultimately controlling the kinetics, texture, and composition of fluid-mineral systems. Applied to some of the world’s most valuable orebodies, these results provide new insights into how early formation of extensive magnetite alteration may have preconditioned these ore systems for later enhanced metal accumulation, contributing to their sizes and metal endowment.

Mass Transfer During Fluid Sphere Dissolution in an Alternating Electric Field

Volume 3 ◽  
2004 ◽  
Author(s):  
Tov Elperin ◽  
Andrew Fominykh ◽  
Zakhar Orenbakh
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Applied Electric Field ◽  
Fluid Motion ◽  
Analytical Form ◽  
Internal Resistance ◽  
Creeping Flow ◽  
Fluid Sphere ◽  
Droplet Deformation ◽  
Alternating Electric Field

In this study we considered mass transfer in a binary system comprising a stationary fluid dielectric sphere embedded into an immiscible dielectric liquid under the influence of an alternating electric field. Fluid sphere is assumed to be solvent-saturated so that an internal resistance to mass transfer can be neglected. Mass flux is directed from a fluid sphere to a host medium, and the applied electric field causes a creeping flow around the sphere. Droplet deformation under the influence of the electric field is neglected. The problem is solved in the approximations of a thin concentration boundary layer and finite dilution of a solute in the solvent. The thermodynamic parameters of a system are assumed constant. The nonlinear partial parabolic differential equation of convective diffusion is solved by means of a generalized similarity transformation, and the solution is obtained in a closed analytical form for all frequencies of the applied electric field. The rates of mass transfer are calculated for both directions of fluid motion — from the poles to equator and from the equator to the poles. Numerical calculations show essential (by a factor of 2–3) enhancement of the rate of mass transfer in water droplet–benzonitrile and droplet of carbontetrachloride–glycerol systems under the influence of electric field for a stagnant droplet. The asymptotics of the obtained solutions are discussed.

Determination of Glucose, Sucrose, Lactose, and Ethanol in Foods and Beverages, Using Immobilized Enzyme Electrodes

1983 ◽  
Vol 66 (4) ◽  
pp. 981-984
Author(s):  
Marc Mason
Keyword(s):  
Hydrogen Peroxide ◽  
Immobilized Enzyme ◽  
Reference Electrode ◽  
Enzyme Electrodes ◽  
Enzyme Substrate ◽  
Platinum Anode ◽  
Cereal Samples ◽  
Sensitive Electrode ◽  
Better Than

Abstract An enzyme electrode coupling immobilized oxidase enzymes with a hydrogen peroxide-sensitive electrode is described. An enzyme or enzymes are immobilized in a thin microporous membrane which titsdirectly over a platinum anode held at +0.700 V relative to a Ag/AgCl2 reference electrode. When an enzyme substrate diffuses into the membrane, hydrogen peroxide is produced. The hydrogen peroxide is then oxidized at the platinum anode, producing anelectrical current that is directly proportional to hydrogen peroxide concentration, and hence substrate concentration. Glucose and sucrose in cereal samples, lactose in cheese, and ethanol in beer and wine were determined using enzyme electrodes. Relative precision of replicate analyses was better than ±2% and agreement with AOAC methods was good.

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