Modelling of immobilised enzyme biocatalytic membrane reactor performance
Journal of Molecular Catalysis B: Enzymatic
Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, South Africa; Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, South Africa; University of Pretoria, Private Bag X20, Hatfield, South Africa
Abstract Immobilised enzyme-catalysed conversions frequently provide specific advantages of selectivity over chemical conversions and further, facilitate continuous operation through biocatalyst retention and reuse. This study focuses on the development and modelling of an enzyme-catalysed continuous immobilised enzyme biocatalytic membrane reactor (BMR). The conversion of the amidase-catalysed lactamide to lactic acid process was used as an industrially representative system with which to evaluate the process performance of the BMR. The model was developed from unsteady state differential mass balances incorporating a second order enzyme decay. This model was validated from empirically determined conversions in dual experiments using 80 and 40 mM amide substrate, 6.4 and 20.1 mg immobilised amidase and a flow rate of 0.0005 and 0.0001 L/min respectively. Model predictions over a range of amidase amounts and stabilities, flow rates and initial amide concentrations quantified the direction and extent of the influence of these parameters on the maximum conversions attainable, consequently identifying the critical parameter ranges defining optimal BMR performance. Although the model has been developed and validated for the prediction of BMR performance of the specific lactamide-lactic acid system, it nevertheless has broad applicability for and relevance to broad-based prediction of the performance of immobilised enzyme BMR processes in general, irrespective of the specific enzyme or substrate moieties. © 2015 Elsevier B.V.
Amides; Bioreactors; Catalysis; Flow rate; Lactic acid; Mathematical models; Biocatalytic membrane reactors; Bioprocesses; Chemical conversions; Continuous operation; Immobilised enzymes; Model prediction; Parameter range; Process performance; Enzymes; amidase; amide; immobilized enzyme; lactic acid; tiopronin; Article; basal metabolic rate; bioprocess; catalysis; concentration (parameters); enzyme immobilization; enzyme substrate; experiment; flow rate; immobilized enzyme reactor; membrane reactor; prediction; validation study
US, Universiteit Stellenbosch