The Sabatier principle governs the performance of self-sufficient heterogeneous biocatalysts for redox biotransformations.

Self-sufficient heterogeneous biocatalysts (ssHBs), in which enzymes and cofactors are coimmobilized on the same support, provide cofactor regeneration and reduce operating costs. However, the underlying mechanisms remain poorly understood. Here, we present a theoretical model for ssHBs consisting of NAD(P)H-dependent dehydrogenases immobilized on porous agarose-based materials with cofactors coimmobilized through electrostatic interactions via a cationic polymer coating. This model links enzyme activity to cofactor-polymer binding thermodynamics and demonstrates that ssHBs obey the Sabatier principle, where maximum catalytic efficiency is achieved at an intermediate binding strength. Adjustment of pH and ionic strength modulates this interaction, and the resulting activity exhibits the predicted volcano plot. Depending on the reaction conditions, electrostatic complexation is influenced, resulting in the formation of a dense, liquid-like phase inside the particles. Our study directly confirms the Sabatier principle in ssHBs and highlights the crucial role of cofactor binding thermodynamics in optimizing biocatalysis for chemical applications.