The improvement of formic acid production from CO2 with visible-light energy and formate dehydrogenase by the function of the viologen derivative with carbamoylmethyl group as an electron carrier

Formate dehydrogenase (FDH) is an attractive biocatalyst for converting CO2 to formic acid in ambient conditions. FDH is applied to the catalyst for the visible-light induced CO2 - formic acid conversion system consisting of an electron donor, a photosensitizaer and an electron carrier. For improvement of the formic acid production efficiency with this system, the enhancement of electron relay processes among a photosensitizer, an electron carrier and FDH has been needed. We aimed to solve this problem by developing novel electron carrier based on the viologen derivative instead of methylviologen (MV), widely used as an electron carreir. In this study, viologen derivatives with carbamoyl group, 1,1'dicarbamoylmethyl-4,4'-bipyridinium diiodide (CV) and 1-carbamoylmethyl-1'-methyl-4,4'-bipyridinium diiodide (CMV) were synthesized and applied to the electron carrier for photoinduced CO2-formic acid conversion system consisting of triethanolamine, water-soluble zinc porphyrin and FDH. By using CV and CMV, the effective formic acid production in the system of water-soluble zinc porphyrin and FDH was improved compared with that of MV. (C) 2017 Elsevier B.V. All rights reserved.