Kinetic models of activity for β-galactosidases: influence of pH, ionic concentration and temperature

Jurado, E.; Camacho, F.; Luzón, G.; Vicaria, José M.

doi:10.1016/j.enzmictec.2003.07.004

Cited by 110 publications

(51 citation statements)

References 23 publications

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“…A reduction of 50% is achieved at 14 min for 40 • C and 226 min for 5 • C. At 50 • C the reaction extent levels off at 45.6% [8]. This demonstrates the fast deactivation of the enzyme at 50 • C, which is in general agreement with the results obtained for this enzyme in aqueous solutions [46]. The outlined dependence of the enzyme activity on temperature represents one of the key challenges for practical applications of β-galactosidase in household environments.…”

Section: Hydrolysis Of Lactosesupporting

confidence: 81%

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

Buckin

Altas

2017

Catalysts

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Abstract:The rapidly growing field of chemical catalysis is dependent on analytical methods for non-destructive real-time monitoring of chemical reactions in complex systems such as emulsions, suspensions and gels, where most analytical techniques are limited in their applicability, especially if the media is opaque, or if the reactants/products do not possess optical activity. High-resolution ultrasonic spectroscopy is one of the novel technologies based on measurements of parameters of ultrasonic waves propagating through analyzed samples, which can be utilized for real-time non-invasive monitoring of chemical reactions. It does not require optical transparency, optical markers and is applicable for monitoring of reactions in continuous media and in micro/nano bioreactors (e.g., nanodroplets of microemulsions). The technology enables measurements of concentrations of substrates and products over the whole course of reaction, analysis of time profiles of the degree of polymerization and molar mass of polymers and oligomers, evolutions of reaction rates, evaluation of kinetic mechanisms, measurements of kinetic and equilibrium constants and reaction Gibbs energy. It also provides tools for assessments of various aspects of performance of catalysts/enzymes including inhibition effects, reversible and irreversible thermal deactivation. In addition, ultrasonic scattering effects in dispersions allow real-time monitoring of structural changes in the medium accompanying chemical reactions.

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Section: Hydrolysis Of Lactosesupporting

confidence: 81%

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

Buckin

Altas

2017

Catalysts

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“…3. The enzyme does not deactivate under the conditions assayed [25] but, when the enzymatic reaction occurred in the RHFB, conversion values were lower than in the jacketed-stirred tank reactor, although the membrane and the liquid film near it offer no appreciable resistance to the transport of substrates and products in the absence of enzyme [14]. Also, Kohlwey and Cheryan [5], Korus and Olson [6], and Jurado et al [14] have observed that the activity of b-galactosidase is lower in the RHFB than in the free state.…”

Section: Ecs Circuitmentioning

confidence: 94%

Kinetic and enzymatic adsorption model in a recirculation hollow-fibre bioreactor

Jurado

Camacho

Luzón

et al. 2005

Bioprocess Biosyst Eng

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A general procedure has been developed to model the behaviour of enzymatic reactions in a membrane bioreactor. This procedure unifies the kinetics of the reaction and the adsorption of the enzyme or enzymatic complexes on the membrane, enabling the selection of the most appropriate kinetic model. The general procedure proposed has been particularized and applied to experimental results obtained with two enzymatic reactions carried out in a hollow-fibre reactor, enzymatic hydrolysis of lactose by beta-galactosidase and glucose-fructose isomerization by glucose isomerase. The application of the general model has allowed us to determine the mechanism of the reaction for both kinetic reactions, assuming the adsorption of the enzymatic complex EGa for lactose hydrolysis and the adsorption of the free enzyme onto the membrane for glucose-fructose isomerization.

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“…It is caused by the combination of different effects such as temperature, concentration of substrate and product, shear stress, etc. [33][34][35] that simultaneously deactivate the enzymes. The mathematical model described the data well (Eqs.…”

Section: Maltose Hydrolysis In the Repetitive Batch Reactormentioning

confidence: 99%

Mathematical modeling of maltose hydrolysis in different types of reactor

Findrik

Presečki

Vasić-Rački

2009

Bioprocess Biosyst Eng

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A commercial enzyme Dextrozyme was tested as catalyst for maltose hydrolysis at two different temperatures: 40 and 65°C at pH 5.5. Its operational stability was studied in different reactor types: batch, repetitive batch, fed-batch and continuously operated enzyme membrane reactor. Dextrozyme was more active at 65°C, but operational stability decay was observed during the prolonged use in the reactor at this temperature. The reactor efficiencies were compared according to the volumetric productivity, biocatalyst productivity and enzyme consumption. The best reactor type according to the volumetric productivity for maltose hydrolysis is batch and the best reactor type according to the biocatalyst productivity and enzyme consumption is continuously operated enzyme membrane reactor. The mathematical model developed for the maltose hydrolysis in the different reactors was validated by the experiments at both temperatures. The Michaelis-Menten kinetics describing maltose hydrolysis was used.List of symbols EC Enzyme consumption (kU g -1 ) K m Michaelis constant (g dm -3 ) k d Enzyme operational stability decay rate constant (min -1 ) q v Flow rate of the reaction solution (cm 3 min -1 ) Q BP Biocatalyst productivity (g kU -1 ) Q p Volumetric productivity (kg dm -3 d -1 )Maximal reaction rate (g dm -3 min -1 )Greek symbols c Concentration (g dm -3 ) u Enzyme concentration expressed as enzyme volume per volume of reaction mixture (cm 3 /cm 3 )

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Kinetic models of activity for β-galactosidases: influence of pH, ionic concentration and temperature

Cited by 110 publications

References 23 publications

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

Kinetic and enzymatic adsorption model in a recirculation hollow-fibre bioreactor

Mathematical modeling of maltose hydrolysis in different types of reactor

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