Multiple steady states in a continuous stirred tank reactor: an experimental case study for hydrolysis of sucrose by invertase

Vásquez-Bahena, J.M.; Montes-Horcasitas, M.C.; Ortega‐López, Jaime; Magaña-Plaza, I.; Flores-Cotera, Luis B.

doi:10.1016/j.procbio.2003.11.007

Cited by 17 publications

(10 citation statements)

References 13 publications

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“…Initial reactions rates of sucrose hydrolysis were determined at diVerent substrate concentrations ranging from 30 mM to 2.0 M of sucrose in 50 mM acetate buVer, pH 5.5 at 30 °C. The kinetic constants were determined as described [29] from Lineweaver-Burk [14], Hanes-Wolf and Eadie-Hofstee plots, and then by the numeric method "lineal Newton" using the Excel solver tool.…”

Section: Evectiveness Factor (F )mentioning

confidence: 99%

“…2a). Optimal Optimal pH values of 5.0-5.5 have been reported for both free and immobilized invertases from bacteria and yeast [3,16,23,29,31]. The eVect of diVerent temperatures, ranging from 25 to 50 °C was also analyzed.…”

Section: Enzymatic Characterization Of Free and Immobilized Inva-cbd mentioning

confidence: 99%

“…This enzyme shows an anticompetitive inhibition through a mechanism involving the reversible binding of substrate on the enzyme molecule at high sucrose concentrations, and experimental evidence of multiple steady states, under deWned operation conditions, in a continuous stirred tank reactor for hydrolysis of sucrose by invertase has been reported [29]. The invertase from S. cerevisiae is inhibited by low concentration of substrate (5%) and does not represent a thermo stable enzyme.…”

Section: Introductionmentioning

confidence: 99%

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Expression, purification and immobilization of the intracellular invertase INVA, from Zymomonas mobilis on crystalline cellulose and Nylon-6

Calixto-Romo¹,

Santiago-Hernández²,

Vallejo-Becerra³

et al. 2008

J Ind Microbiol Biotechnol

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This paper presents two immobilization methods for the intracellular invertase (INVA), from Zymomonas mobilis. In the first method, a chimeric protein containing the invertase INVA, fused through its C-terminus to CBDCex from Cellulomonas fimi was expressed in Escherichia coli strain BL21 (DE3). INVA was purified and immobilized on crystalline cellulose (Avicel) by means of affinity, in a single step. No changes were detected in optimal pH and temperature when INVA-CBD was immobilized on Avicel, where values of 5.5 and 30 degrees C, respectively, were registered. The kinetic parameters of the INVA-CBD fusion protein were determined in both its free form and when immobilized on Avicel. Km and Vmax were affected with immobilization, since both showed an increase of up to threefold. Additionally, we found that subsequent to immobilization, the INVA-CBD fusion protein was 39% more susceptible to substrate inhibition than INVA-CBD in its free form. The second method of immobilization was achieved by the expression of a 6xHis-tagged invertase purified on Ni-NTA resin, which was then immobilized on Nylon-6 by covalent binding. An optimal pH of 5.5 and a temperature of 30 degrees C were maintained, subsequent to immobilization on Nylon-6 as well as with immobilization on crystalline cellulose. The kinetic parameters relating to Vmax increased up to 5.7-fold, following immobilization, whereas Km increased up to 1.7-fold. The two methods were compared showing that when invertase was immobilized on Nylon-6, its activity was 1.9 times that when immobilized on cellulose for substrate concentrations ranging from 30 to 390 mM of sucrose.

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Section: Evectiveness Factor (F )mentioning

confidence: 99%

Section: Enzymatic Characterization Of Free and Immobilized Inva-cbd mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Expression, purification and immobilization of the intracellular invertase INVA, from Zymomonas mobilis on crystalline cellulose and Nylon-6

Calixto-Romo¹,

Santiago-Hernández²,

Vallejo-Becerra³

et al. 2008

J Ind Microbiol Biotechnol

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“…This reaction system is well known and its characteristics have already been investigated in several papers [10,[14][15][16][17][18][19][20][21][22]. In our study, we chose the strong acidic cation exchange resin Amberlite IR-120 in H ?…”

Section: Introductionmentioning

confidence: 99%

A kinetic study of sucrose hydrolysis over Amberlite IR-120 as a heterogeneous catalyst using in situ FTIR spectroscopy

Zajšek

Goršek

2010

Reac Kinet Mech Cat

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This work describes the experimental determination of sucrose hydrolysis kinetics using a heterogeneous catalyst. We used an Amberlite IR-120 strong acidic cation-exchange resin. The experiments were performed under previously determined optimal process conditions: sucrose mass concentration, c S = 50 g L -1 , catalyst mass concentration, c C = 180 g L -1 , rotational frequency of the stirrer f m = 180 min -1 , and temperature 0 = 79°C. The parameters of the supposed kinetic model were determined using experimental data. The kinetics of sucrose hydrolysis over Amberlite IR-120 has not been reported to date. Therefore, we could not directly compare the calculated values of kinetic parameters with those from the literature. However, the calculated values are within the range of values determined by other types of catalysts. Furthermore, we investigated the influence of catalyst mass concentration c C on the reaction rate constant k 0 . List of symbolsInitial concentration of sucrose (mol L -1 ) dPath length E a Activation energy (kJ mol -1 ) f m Rotational frequency of the stirrer (min -1 ) F Statistical F-criterion (variance ratio), 1 k 0Reaction rate constant (L kg -1 min -1 ) k 0 0 Pre-exponential factor (L kg -1 min -1 ) m C Mass of catalyst (kg) PRESS Predicted residual error sum of squares, 1 r S 0 Rate of reaction based on the mass of catalyst (mol kg -1 min -1 ) R Universal gas constant (J mol -1 K -1 ) RMultiple correlation coefficient (-) R 2Coefficient of determination (-) R adj 2

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“…5.1. The most used are the packed-bed column reactors (Marrazzo et al 1975;Munro et al 1981;Verhoff and Schlager 1981) where the immobilized enzyme is fixed within the reactor while the substrate stream passes through, and the stirred tank reactor where the enzyme is retained in the reactor by an appropriate screen or recovered by ex-situ filtration or centrifugation and recycled back into the reactor (Vásquez-Bahena et al 2004). An alternative is the expanded or fluidized bed reactor (Allen et al 1979;Ching and Chu 1988) where the enzyme particles are retained by a hydrodynamic balance between gravity and drag forces promoted by the upflow substrate stream.…”

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confidence: 99%

Enzyme Reactors

Illanes

Altamirano

2008

Enzyme Biocatalysis

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More than 80% of the commercial value of enzymes is linked to their applications as process catalysts. Hydrolytic reactions conducted mainly with the enzyme dissolved in the aqueous medium has been the traditional way of using enzymes, this technology still representing a major share of enzyme processes. However, in recent decades the use of enzymes in organic synthesis has widened its scope of application to unprecedented levels.Enzyme reactors can operate batch-wise or continuously; fed-batch operation has also been proposed (Kumar et al. 1996). Batch processes with the enzymes (usually hydrolases) dissolved in an aqueous reaction medium, despite its wide application have several drawbacks, since enzymes are poorly stable and hard to recover in such systems, leading to low productivity; besides, such processes are characterized by a rather low added value so that process optimization is critical for being and keeping competitive. Poor stability is usually the limiting factor in any enzyme process so that enzyme stabilization during reactor operation is a major concern (Ballesteros et O'Fágáin 2003) and among the many strategies for enzyme stabilization (Illanes 1999) enzyme immobilization is the most relevant (Guisán 2006). Immobilized enzymes can be used in batch processes but in this case the enzyme is recovered to be used in subsequent batches until the accumulated inactivation makes necessary to replace the spent biocatalyst. As a consequence, specific productivity (mass of product/mass of biocatalyst · time of operation) is increased and bioreactor design becomes flexible to suit the particular needs of a given process.Immobilized enzymes, despite the complexities introduced by the heterogeneous nature of the catalytic process, are usually much more stable than their soluble

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Multiple steady states in a continuous stirred tank reactor: an experimental case study for hydrolysis of sucrose by invertase

Cited by 17 publications

References 13 publications

Expression, purification and immobilization of the intracellular invertase INVA, from Zymomonas mobilis on crystalline cellulose and Nylon-6

Expression, purification and immobilization of the intracellular invertase INVA, from Zymomonas mobilis on crystalline cellulose and Nylon-6

A kinetic study of sucrose hydrolysis over Amberlite IR-120 as a heterogeneous catalyst using in situ FTIR spectroscopy

Enzyme Reactors

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