Electrochemically driven efficient enzymatic conversion of CO2 to formic acid with artificial cofactors. Issue 52 (October 2021)

• Record Type: Journal Article
• Authors: Zhang, Zhibo; Vasiliu, Tudor; Li, Fangfang; Laaksonen, Aatto; Mocci, Francesca; Ji, Xiaoyan
• Is Part Of: Journal of CO₂ utilization. Issue 52(2021)
• Publication Date: 2021-10
• Subjects: CO2 conversion -- Formic acid -- Enzyme -- Artificial cofactors -- Electrocatalysis -- Umbrella sampling -- Molecular dynamics; Carbon dioxide -- Periodicals; Carbon dioxide -- Environmental aspects -- Periodicals; Carbon dioxide mitigation -- Periodicals; Carbon dioxide; Carbon dioxide -- Environmental aspects; Carbon dioxide mitigation; Periodicals; 628.53205
• DOI: 10.1016/j.jcou.2021.101679
• Languages: English
• ISSNs: 2212-9820

Abstract

Graphical abstract: Integration of electro-regeneration of artificial cofactor and enzymatic conversion of CO2 for bioelectrocatalytic formic acid production in a sustainable way. Highlights: Development of bipyridine-based artificial cofactors for enzymatic conversion of CO2 . Kinetics, thermodynamics, and equilibrium constant investigation. Catalytic efficiency ( k cat / K m ) was 536 times higher than that of the natural cofactor. Mechanism investigation by molecular dynamic simulation. Abstract: Enzymatic reduction of CO2 to formic acid with the enzyme formate dehydrogenase (FDH) and a cofactor is a promising method for CO2 conversion and utilization. However, the natural cofactor nicotinamide adenine dinucleotide (NADH) shows some drawbacks such as a low reduction efficiency and forms isomers or dimers (1, 6 - NADH or NAD dimer) in the regeneration reaction. To overcome them and to improve the production of formic acid, in this work, the artificial cofactors, i.e., the bipyridinium-based salts of methyl viologen (MV 2+ ), 1, 1'-dicarboxymethyl-4, 4'-bipyridinium bromine (DC 2+ ), and 1, 1'-diaminoethyl-4, 4'-bipyridinium bromine (DA 2+ ), were used to replace NADH, and the effect of different functional groups on the electrochemical regeneration and catalytic performance in the enzymatic reaction was studied systematically. Also, studies using the natural cofactor NADH were carried out for comparison. It was found that the cofactor with amino groups showed the highest catalytic efficiency ( k cat / K m ) of 0.161 mM -1 min -1, which is 536 times higher than that of the natural cofactor NADH. Molecular Dynamics simulations were conducted to give further molecular insight into the behavior of the cofactors. Analyzing the free energy profiles of the complexes between CO2 in the FDH active site with different artificial cofactors indicated that the artificial cofactor with the amino groups had the highest affinity for CO2, being consistent with the experimental observations.