title: Development of a dye molecule-biocatalyst hybrid system with visible-light induced carbon-carbon bond formation from CO2as a feedstock.
abstract: Recently, CO2utilization technology, including artificial photosynthesis, has received much attention. In this field, CO2is used as a feedstock for fuels, polymers and in other chemical processes. Of note are malic enzymes (MEs) which catalyze the reaction of malic acid to pyruvic acid and CO2with the co-enzyme NADP+, and catalyze the reverse reaction of pyruvic acid and CO2to malic acid with the co-enzyme NADPH. Thus, MEs are also an attractive biocatalyst for carbon-carbon bond formation from CO2. Studies of the visible light-induced malic acid production from pyruvic acid and CO2using an electron donor, a photosensitizer, an electron mediator, ferredoxin-NADP+reductase, NADP+, and ME have been reported. However, modification of these systems is required, as they are very complicated. In this study, the visible light-induced carbon-carbon bond formation from pyruvic acid and CO2with ME using the photoreduction of 1,1'-diphenyl-4,4'-bipyridinium salt derivatives as a novel electron mediator with water-soluble tetraphenylporphyrin tetrasulfonate (H2TPPS) in the presence of triethanolamine (TEOA) as an electron donor was developed. When a sample solution containing TEOA, H2TPPS, 1,1'-diphenyl-4,4'-bipyridinium salt derivative, pyruvic acid, and ME in CO2-saturated bis-tris buffer was irradiated, the major product was oxaloacetic acid. Thus, a visible light-induced photoredox system for carbon-carbon bond formation from CO2with ME using 1,1'-diphenyl-4,4'-bipyridinium salt derivative as an electron mediator was developed.
authors.affiliation: The Advanced Research Institute for Natural Science and Technology, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan. amao@ocarina.osaka-cu.ac.jp.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Amao
authors.forename: Shusaku
authors.initials: S
authors.lastname: Ikeyama
authors.forename: Takayuki
authors.initials: T
authors.lastname: Katagiri
authors.forename: Kohei
authors.initials: K
authors.lastname: Fujita