Simulation of glucose isomerase reactor: optimum operating temperature
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Abstract
A design equation for immobilized glucose isomerase (IGI) packed bed reactor is developed assuming enzyme deactivation and substrate protection. The developed equation is used to simulate the performance of the reactor at various temperatures (50–80 °C). Enzyme deactivation is significant at high temperature. Substrate protection showed to have significant effect in reducing enzyme deactivation and increasing the enzyme half-life. Factors affecting the optimum operating temperature are discussed. The optimum operating temperature is greatly influenced by the operating period and to a lesser extent with both initial glucose concentration and glucose conversion.
Two modes of reactor operation are tested i.e., constant feed flow rate and constant conversion. Reactor operating at constant conversion is more productive than reactor operating at constant flow rate if the working temperature is higher than the optimum temperature. Although at lower temperatures than the optimum, the two modes of operation give the same result.
Keywords
Isomerase Constant Flow Rate Feed Flow Rate Reactor Operation Design EquationList of Symbols
- a
residual enzyme activity
- E [mg/l]
concentration of active enzyme
- Ea [kJ/mole]
activation energy
- E0 [mg/l]
initial concentration of active enzyme
- k [Specific]
kinetic parameter
- kd [h–1]
first order thermal deactivation rate constant
- ke
equilibrium constant
- km [mole/l]
apparent Michaelis constant
- kp [mole/l]
Michaelis constant for product
- ks [mole/l]
Michaelis constant for substrate
- k0 [Specific]
pre-exponential factor
- Q [1/h]
volumetric flow rate
- ¯Q [1/h]
average volumetric flow rate
- R [kJ/mol·k]
ideal gas constant
- s′ [mole/l]
apparent substrate concentration
- s [mole/l]
substrate concentration
- se [mole/l]
substrate concentration at equilibrium
- s0 [mole/l]
substrate concentration at reactor inlet
- p [mole/l]
product concentration
- pe [mole/l]
product concentration at equilibrium
- Pr [mole fructose/l·h]
reactor productivity
- T [k]
temperature
- t [h]
time
- tp [h]
operating time
- V [l]
reactor volume
- v [mole/l·h]
reaction rate
- v′ [mole/l]
reaction rate under enzyme deactivation and substrate protection
- vm [mole/l·h]
maximum apparent reaction rate
- vp [mole/l·h]
maximum reaction rate for product
- vs [mole/l·h]
maximum reaction rate for substrate
- x
substrate fractional conversion
- xe
substrate fractional conversion at equilibrium
Greek Symbols
- η
effectiveness factor
- \(\bar \eta \)
mean effectiveness factor
- σ
substrate protection factor
- τ [h]
residence time
- \(\bar \tau \) [h]
average residence time
- τ0 [h]
initial residence time
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References
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