engleski

Modeling and kinetic parameter estimation of alcohol dehydrogenase-catalyzed hexanol oxidation in a microreactor

A focus of this work was to investigate change in kinetics of enzyme reaction in two immiscible phase systems (water and organic phase) in a macroscopic reactor and microreactors. For this purpose, a mathematical model for the hexanol oxidation catalysed by NAD+ dependent alcohol dehydrogenase from baker’s yeast in a microreactor was developed and compared with the model when the reaction takes place in a macroscopic reactor. Enzyme kinetics was modelled as a pseudohomegeneous process with the double substrate Michaelis-Menten rate expression. In comparison with kinetic parameters estimated in the cuvette 30 fold higher maximum reaction rate and relatively small change in the saturation constants is observed for the kinetic parameters estimated in the continuously operated tubular microreactor (Vm1 = 197.275 U mg-1, Kmhexanol = 9.420 mmol dm-3 and Km1NAD+ = 0.187 mmol dm-3). Kinetic measurements performed in microreactor estimated from the initial reaction rate experiments at the residence time of 36 s showed no product inhibition explained with hydrodynamic effects (all experiments were performed in the slug flow regime) and continuous removal of inhibiting products. Fourier amplitude sensitivity test method was applied for the global kinetic parameter analysis which shows significant increase in sensitivity of Km1NAD+ in the microreactor. Independent experiments performed in microreactor were used to validate and to verify the developed mathematical model. Good agreement between the model predictions and experimental results was achieved, indicating that developed model could be used for process optimisation and scale-up (numbering-up) of microreactors.

microreactor ; alcohol dehydrogenase ; hexanol oxidation ; mathematical modelling

Ovaj se tekst temelji na radu koji je financirala Nacionalna zaklada za znanost, visoko školstvo i tehnologijski razvoj Republike Hrvatske.