Screening Platform for Immobilized Biocatalysts Utilizing Miniature Rotating Bed Reactors

Biocatalysis has matured to become a technology widely applied in the chemical industry. There are numerous potential routes to improve the performance of a biocatalytic process. Immobilizing enzymes can be advantageous as it increases stability and simplifies separating enzymes from reaction mixtures. However, establishing a biocatalytic process based on immobilized enzymes is expensive, time-consuming, and labor-intensive. The reason for this is that a multitude of parameters influence the outcome of the immobilization and the performance in the final process. Screening these parameters in parallel on a small scale is a common strategy to address these issues. However, when screening immobilized enzymes with established methods such as centrifuge tubes, the reaction conditions differ substantially from the process conditions. We present a novel screening platform for immobilized enzymes based on magnetically driven miniature rotating bed reactors (MiniRBRs) to overcome this. This system unites the advantages of small scale operation with immobilizates and the application of rotating bed reactors, which are already established to be scalable at an industrial scale. As a model system, the synthesis of acetyl phosphate from glycolaldehyde catalyzed by a phosphoketolase is used in this study. We were able to significantly increase the stability of the phosphoketolase by immobilizing the phosphoketolase and using the MiniRBR system. In addition, the versatility of the MiniRBR will be demonstrated in terms of compatibility with different enzyme carrier materials, reaction conditions, and modes of operation.