SynHydro³ – Synthesis Platform Using Hydrogen, Hydrogenases and Hydrogels

Challenges

Until now, hydrogen-driven biocatalysis in the form of a modular and scalable platform technology has not been implemented due to the lack of highly active, robust, and scalable hydrogen-oxidizing biocatalysts that are functional under industrially relevant process conditions. Hydrogenases are promising candidates for using hydrogen as an electron donor for synthesis, but they are often too unstable due to their high sensitivity to oxygen.

Results

The SynHydro³ project has now succeeded in embedding specially selected hydrogenases together with other enzymes in redox-active polymers in such a way that they can be used in a variety of ways for synthesis, with technical hydrogen acting as an electron donor. To this end, novel biohybrid catalytic microdisks made of a redox hydrogel were developed for the stable and functional integration of the hydrogenases and to protect them from oxidative damage, and were implemented for the hydrogen-driven enzyme cascades. The design of the hybrid system facilitates the handling, storage, and use of these hydrogenases in air and enables catalytic processes with oxygen as a co-substrate.

The scalable production of the redox hydrogel microdisks has also been successfully demonstrated. These contain all the enzymes required for cofactor regeneration to operate oxygen-dependent enzyme cascades with hydrogen as the electron source. The results have been submitted as a patent application and are currently being prepared for publication. Industrial feasibility will be further advanced in follow-up projects.

Advantages and impact

This recyclable biohybrid system will serve as a compatible platform technology using existing bioreactor infrastructure and enable the decarbonization of biocatalytic processes by replacing traditional carbon-rich electron donors.