Modelling of two enzyme reactions in a linked cofactor recycle system for chiral lactone synthesis

A model has been developed to describe the interaction between two enzymes in a stirred vessel. Using the model, cofactor (NADPH) recycle has been inv estigated by simultaneous solution of the rate equations, solved with the a id of a numerical solution. The overall general aim of this work is to incr ease the information available to the designer on similar biocatalytic proc esses so that comparisons between process options can be quantified. This m odel allows the optimisation of the proportion of two enzymes and total cof actor concentration needed for a satisfactory reaction rate to be achieved. A secondary use of these data is in the prediction of cofactor stability w hich is a strong function of pH. The model also indicates the potential cof actor turnover number achievable, an important economic consideration. The accuracy of the model has been assessed and is in good agreement with exper imental data. (C) 2000 Elsevier Science Ltd. All rights reserved.