Kinetic study of fructose‐glucose isomerization in a recirculation reactor

Camacho-Rubio, F.; Alameda, Encarnación Jurado; González-Tello, P.; Luzón-González, Germán

doi:10.1002/cjce.5450730618

Cited by 17 publications

(8 citation statements)

References 22 publications

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“…The following correlations have been reported for D ‐glucose isomerization using Sweetzyme type T® immobilized enzyme, which satisfactorily fit experimental data concerning the reaction56: where T is temperature in K.…”

Section: Reaction Kineticssupporting

confidence: 73%

Novel type of two‐impinging‐jets reactor for solid–liquid enzyme reactions

Dehkordi

2005

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com). The isomerization of D-glucose to D-fructose using the immobilized glucose isomerase, as a typical model system of solid-liquid enzyme reactions has been carried out in a novel type of two-impinging-jets reactor (TIJR), which is characterized by a rotating inner cylinder in a stationary one. Because of the impinging process, turbulence, and complex trajectory of the solid particles within the reactor, the fractional conversion of glucose obtained in the TIJR increased dramatically compared to that obtained by conventional reaction systems. A compartment model was considered to describe the pattern of flow [residence time distribution (RTD) of solid particles] within the TIJR. Considering such a flow pattern, a stochastic model for the RTD of the solid particles was developed using Markov chains models. The latter was correlated with the experimental RTD data, obtained by using a tracer analysis technique. © 2005 American Institute of ChemicalEngineers AIChE J, 52: 692-704, 2006 Keywords: impinging jets, opposed jets, glucose isomerase, enzymatic isomerization, residence time distribution IntroductionSolid-liquid enzyme reactions constitute important processes in biochemical industries. Among the latter, the isomerization of glucose to fructose is one of the most widely used processes in the food industry in producing dietetic "light" foods and drinks because it improves the sweetening, color, and hygroscopic characteristics in addition to reducing viscosity. Also, fructose is about 75% sweeter than sucrose, is absorbed more slowly than glucose, and is metabolized without the intervention of insulin. For all these reasons, this process is widely studied both with cells and with enzymes, both free and immobilized (IE). [1][2][3][4][5][6][7][8][9][10][11][12][13] From the perspective of chemical kinetics, isomerization of glucose to fructose is a reversible reaction, with an equilibrium constant of approximately unity at 55°C. 14 The heat of reaction is on the order of 5 kJ/mol 14 and, consequently, the equilibrium product contains roughly a 1:1 ratio of glucose to fructose that does not change appreciably with temperature, such that at 55°C the fructose content at equilibrium is 50%, and at higher temperatures such as 60, 70, 80, and 90°C is 50.7, 52.5, 53.9, and 55.6%, respectively. However, increasing temperature decreases stability and the enzyme half-life and therefore productivity. Most industrial plants run at 58 -60°C, a temperature with low risk for microbial contamination.The process was originally carried out in batch reactors with soluble enzymes. It was later extended to one involving immobilized glucose isomerase (IGI), which is of interest to us in the present work. In addition to the aforementioned batch reactors, there are various types of enzyme reactors, including continuous stirred tank reactors (CSTR), fixed-bed reactors, simulated moving beds, and fluidized-bed reactors. In the fixed-and fluidized-bed reactors, the enzymes are immobilized ...

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Section: Reaction Kineticssupporting

confidence: 73%

Novel type of two‐impinging‐jets reactor for solid–liquid enzyme reactions

Dehkordi

2005

AIChE Journal

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“…K eq Fructose eq Glucose eq 3 K H m 1 K mr À K mf K mr K mf K eq Glu eq K mr K mf 4 where K mf , K mr are Michaelis±Menten constants for forward and reverse reactions, respectively; V maxf , V maxr are maximum rates for the forward and reverse reactions, respectively; and G is [Glu] ) [Glu] eq . Figure 3 of Camacho-Rubio et al (1995) shows a plot of K mf versus K mr for many different GIs. Most of the data lie on the 45°line, indicating that these parameters are approximately equal, a ®nding also noted by Palazzi and Converti (1999).…”

Section: Tngi and Smgi Productivities At Elevated Temperaturesmentioning

confidence: 99%

Glucose‐to‐fructose conversion at high temperatures with xylose (glucose) isomerases from Streptomyces murinus and two hyperthermophilic Thermotoga species

Bandlish

Hess

Epting

et al. 2002

Biotech & Bioengineering

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The conversion of glucose to fructose at elevated temperatures, as catalyzed by soluble and immobilized xylose (glucose) isomerases from the hyperthermophiles Thermotoga maritima (TMGI) and Thermotoga neapolitana 5068 (TNGI) and from the mesophile Streptomyces murinus (SMGI), was examined. At pH 7.0 in the presence of Mg(2+), the temperature optima for the three soluble enzymes were 85 degrees C (SMGI), 95 degrees to 100 degrees C (TNGI), and >100 degrees C (TMGI). Under certain conditions, soluble forms of the three enzymes exhibited an unusual, multiphasic inactivation behavior in which the decay rate slowed considerably after an initial rapid decline. However, the inactivation of the enzymes covalently immobilized to glass beads, monophasic in most cases, was characterized by a first-order decay rate intermediate between those of the initial rapid and slower phases for the soluble enzymes. Enzyme productivities for the three immobilized GIs were determined experimentally in the presence of Mg(2+). The highest productivities measured were 750 and 760 kg fructose per kilogram SMGI at 60 degrees C and 70 degrees C, respectively. The highest productivity for both TMGI and TNGI in the presence of Mg(2+) occurred at 70 degrees C, pH 7.0, with approximately 230 and 200 kg fructose per kilogram enzyme for TNGI and TMGI, respectively. At 80 degrees C and in the presence of Mg(2+), productivities for the three enzymes ranged from 31 to 273. A simple mathematical model, which accounted for thermal effects on kinetics, glucose-fructose equilibrium, and enzyme inactivation, was used to examine the potential for high-fructose corn syrup (HFCS) production at 80 degrees C and above using TNGI and SMGI under optimal conditions, which included the presence of both Co(2+) and Mg(2+). In the presence of both cations, these enzymes showed the potential to catalyze glucose-to-fructose conversion at 80 degrees C with estimated lifetime productivities on the order of 2000 kg fructose per kilogram enzyme, a value competitive with enzymes currently used at 55 degrees to 65 degrees C, but with the additional advantage of higher fructose concentrations. At 90 degrees C, the estimated productivity for SMGI dropped to 200, whereas, for TNGI, lifetime productivities on the order of 1000 were estimated. Assuming that the most favorable biocatalytic and thermostability features of these enzymes can be captured in immobilized form and the chemical lability of substrates and products can be minimized, HFCS production at high temperatures could be used to achieve higher fructose concentrations as well as create alternative processing strategies.

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“…where K eq is the equilibrium constant of the reaction, [11,13,23,24] and the reaction rate constants are given as follows:…”

Section: Free Enzyme Kineticsmentioning

confidence: 99%

“…), similar to a free enzyme reaction system. The mathematical model (Equations (11), (13), and (14)) was simultaneously adjusted using all the experimental data shown in Figure 3 and η = 0.553. Interestingly, these parameters are adequate for all three different concentrations of enzyme, which suggests that the immobilizing support (calcium alginate matrix) is mainly responsible for establishing the phenomenological behaviour of the EDC and the FREA.…”

Section: Immobilized Enzyme Kineticsmentioning

confidence: 99%

A new approach for describing and solving the reversible Briggs‐Haldane mechanism using immobilized enzyme

et al. 2019

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Recently immobilized enzymes have been widely used in industrial processes due to their outstanding advantages, such as high stability and recyclability; however, their kinetic behaviour is generally controlled by mass diffusion effects. Thus, in order to improve these enzymatic processes, a clear discernment between the kinetic and diffusion mechanisms that control the production of the metabolite require investigation. In practice, it is typical to establish apparent kinetics for immobilized enzyme operations, and the validity of the apparent kinetics is restricted to the studied cases. In this work, a new approach for mathematically describing the kinetic and diffusion mechanics in an immobilized biocatalyst bead is established, in which the fraction of residual enzymatic activity is included, and is defined as a measure of the active and available enzymes in the bead porous network. In addition, the diffusion and kinetic mechanisms are described by the effective diffusion coefficient and the free enzyme kinetics, since the porous network of the bead is assumed as the bioreaction volume. Therefore, free enzyme kinetics were determined from glucose to fructose bioconversion using a stirred tank reactor with free glucose‐isomerase, in which substrate and enzyme concentrations and temperature were varied. The fraction of residual enzymatic activity (η=0.553) and the effective diffusion coefficient (Deff=normal8.356×10−12m2/normals) were obtained from the isomerization of glucose to fructose using a stirred tank reactor with immobilized glucose‐isomerase in calcium alginate beads at different substrate and enzyme concentrations. Finally, simulations were carried out to establish the bioreaction solid‐phase characteristics that most significantly influence productivity.

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Kinetic study of fructose‐glucose isomerization in a recirculation reactor

Cited by 17 publications

References 22 publications

Novel type of two‐impinging‐jets reactor for solid–liquid enzyme reactions

Novel type of two‐impinging‐jets reactor for solid–liquid enzyme reactions

Glucose‐to‐fructose conversion at high temperatures with xylose (glucose) isomerases from Streptomyces murinus and two hyperthermophilic Thermotoga species

A new approach for describing and solving the reversible Briggs‐Haldane mechanism using immobilized enzyme

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