Optimal control of scheduling and production for a multienzymatic system in continuous reactors

Abstract

Enzyme inactivation significantly impacts reactor performance by reducing substrate conversion and product quality. This study, with its focus on optimizing the economic benefits of a novel two-step biocatalytic system, aims to control biocatalyst replacement intervals and operational conditions, thereby enhancing the economic viability of biocatalytic processes. The results demonstrate that optimal control strategies can be effectively implemented for Continuous Stirred Tank Reactors (CSTRs) and Packed Bed Reactors (PBRs). Moreover, PBRs show distinct advantages due to their enhanced capacity to meet demand, primarily resulting from differences in mixing patterns and the extended contact time between reactants and the biocatalyst. An essential contribution of this work is the detailed spatial analysis of temperature distribution within the PBR, an innovative approach to studying multienzyme systems. Considering a 16-week time horizon, the application of the proposed methodology resulted in a total of 3 catalyst changeovers for the CSTR configuration, and one for the PBR, achieving 80% of the total seasonal demand. Furthermore, the development of a comprehensive model that integrates two-stage enzyme inactivation, diffusional limitations, and Michaelis–Menten kinetics for both enzymes provides a thorough understanding and valuable insights into determining optimal biocatalyst replacement times. This approach advances the design and operation of biocatalytic processes for improved economic performance.