Characterization and evaluation of immobilized enzymes for applications in flow reactors

Flow biocatalysis mainly exploit immobilized enzymes for continuous chemical manufacturing. In the last decade, the use of immobilized biocatalysts in flow is growing rapidly, yet the immobilization protocols need to be optimized. In this review, we have discussed the most fundamental aspects to be considered when designing immobilized enzymes for productive and stable operations in flow. Furthermore, we analyze the protein loading, the activity recovery, the space-time yield (STY), the specific productivity and the turnover number, as complementary metrics to assess the efficiency and longevity of immobilized enzymes integrated into flow reactors. The science of the immobilization implies the engineering of the surface protein interface, the material features and the reactor design to achieve highly active and robust heterogeneous biocatalysts under continuous operations. Hence, we encourage the flow biocatalysis community to accompany those engineering efforts with accurate assessments of both activity and stability.