Framework of the kinetic analysis of O2-dependent oxidative biocatalysts for reaction intensification

Abstract

The application of oxygen-dependent enzymes is limited by the low oxygen solubility, a fact that hinders the full operational exploitation of the enzyme activity. This oxygen limitation also creates a difficulty for understanding the intrinsic enzyme kinetics, a critical aspect for the process implementation of oxidative enzymes. Kinetic analysis of O₂-dependent enzymes is a case of ping-pong bi-substrate reaction kinetics but with the added feature of a fixed low concentration of oxygen dissolved in the liquid medium. We propose an analysis framework based on a combination of differential methods (based on initial reaction rates-concentration plots) to analyze the main substrate dependency, while the subsequent integral method (consumption time courses of oxygen dissolved) serves to analyze the oxygen dependency. The methodology is applicable by using the oxygen initially dissolved and only working with liquid suspensions. The analysis was applied to paradigmatic case studies with importance in modern green biooxidations. The modeling framework was validated and applied in scale-up reactions in an instrumented aerated stirred tank reactor.