Development of an Ionic Porphyrin-Based Platform as a Biomimetic Light-Harvesting Agent for High-Performance Photoenzymatic Synthesis of Methanol from CO2

NADH is a required cofactor for enzymatic hydrogenation of CO2 to methanol, but the high costs of NADH deter its large-scale application. Photocatalytic reduction of NAD(+) to NADH is a promising solution that utilizes limitless solar energy. The success of photocatalytic reduction of NAD(+) depends on the use of a photosensitizer that must enable efficient electron transfer from the photosensitizer to the catalyst. Among the evaluated photosensitizers, ionic porphyrin (ZnTPyPBr) was found to be the most efficient photosensitizer for in situ NADH regeneration. Compared to the free system (control), methanol concentration was increased sevenfold when a membrane was used as a support to integrate cascade enzymatic reaction and NADH regeneration.

Automated summary

NADH is essential for enzymatic hydrogenation of CO2 to methanol, but its high costs limit its large-scale application. Photocatalytic reduction of NAD(+) to NADH is a promising solution utilizing solar energy. Efficient electron transfer from the photosensitizer to the catalyst is crucial for the success of NADH regeneration. Ionic porphyrin was identified as the most efficient photosensitizer for in situ NADH regeneration, leading to a sevenfold increase in methanol concentration when integrated with enzyme cascade reactions using a membrane support.