Combining a Genetically Engineered Oxidase with Hydrogen‐Bonded Organic Frameworks (HOFs) for Highly Efficient Biocomposites

Abstract

Enzymes incorporated into hydrogen‐bonded organic frameworks (HOFs) via bottom‐up synthesis are promising biocomposites for applications in catalysis and sensing. Here, we explored synthetic incorporation of d‐amino acid oxidase (DAAO) with the metal‐free tetraamidine/tetracarboxylate‐based BioHOF‐1 in water. N‐terminal enzyme fusion with the positively charged module Z _basic2 strongly boosted the loading (2.5‐fold; ≈500 mg enzyme g _material ⁻¹) and the specific activity (6.5‐fold; 23 U mg ⁻¹). The DAAO@BioHOF‐1 composites showed superior activity with respect to every reported carrier for the same enzyme and excellent stability during catalyst recycling. Further, extension to other enzymes, including cytochrome P450 BM3 (used in the production of high‐value oxyfunctionalized compounds), points to the versatility of genetic engineering as a strategy for the preparation of biohybrid systems with unprecedented properties.

Abstract

Immobilization of d‐amino acid oxidase in crystalline frameworks at high protein loading is reported. A biocomposite of hydrogen‐bonded organic framework (BioHOF‐1) shows excellent retention of activity. Fusion to the positively charged module Z _basic2 (Z‐DAAO) promotes incorporation of the active enzyme. Protein engineering can facilitate development of framework‐based enzyme composites, as shown with three further examples of industrial enzymes.