Model-based heuristic optimized operating policies for d-glucose oxidation in a batch reactor with pulsate addition of enzyme

Model-based optimization of batch enzymatic/bio-reactors is an intensively studied problem due to the increased economic benefits offered by the predicted optimal operating policies. The enzymatic oxidation of d-glucose (DG) in a batch reactor is a process of industrial interest, leading to production of “rare sugars” (keto-derivatives) from monosaccharides. The enzyme activity is sensitive to operating conditions, deactivation occurring due to some of the products and impurities. To keep a high catalytic activity during the batch, a pulsate addition of enzyme solution is performed under some restrictions. By imposing the maximum batch operation time and injected volume, operating policies maximizing the DG-conversion can be derived for every batch case. In the present study, by accounting the process kinetic characteristics, a pulse-injection control function, of exponential type, is proved to be easily adaptable for the optimization of the batch reactor. The heuristic near optimal solution is simple, flexible and can efficiently replace the optimal impulse-fed-policy derived by means of the time-consuming classical direct methods. The heuristic rule, based on the process kinetic model and on a library of semi-empirical functions, can be easily applied to optimize various batch enzymatic processes.