title: Specific and sustainable bioelectro-reduction of carbon dioxide to formate on a novel enzymatic cathode.
abstract: To specifically convert waste CO2 into renewable chemicals, enzymatic electrosynthesis (EES) of formate from CO2 reduction was investigated in a bioelectrochemical system (BES). A novel cathode with immobilized enzyme and electropolymerized mediator-regenerator was fabricated for such bioelectrocatalytic EES. Formate dehydrogenase from Candida boidinii (CbFDH) was set as a new model enzyme in BES. Modified Nafion micelles with appropriate pore size were found to be suitable for immobilization of CbFDH and protection of its enzymatic activity and lifetime at optimal pH of 6.0. The enzymatic electrosynthesis activity of immobilized CbFDH was characterized systematically. Quite a small overpotential was required in the bioelectrochemical EES reaction. A two-electron transfer process was confirmed in the CbFDH-catalyzed reduction of bicarbonate to formate. With electro-polymerized neutral red (PolyNR) as a NADH (mediator)-regenerator, efficient formate production could be achieved at a maximum rate of 159.89 mg L(-1) h(-1) under poised potential of -0.80 V (vs. SHE). The immobilized CbFDH and electropolymerized PolyNR on an enzymatic cathode contributed greatly to sustainable EES, giving energy-rich formate as the only catalysis product.
authors: Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 117543, Singapore.
authors: Lijuan
authors: L
authors: Zhang
authors: Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 117543, Singapore.
authors: Junyi
authors: J
authors: Liu
authors: Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 117543, Singapore.
authors: Jacky
authors: J
authors: Ong
authors: Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 117543, Singapore; NUS Environmental Research Institute, National University of Singapore, Singapore 117411, Singapore. Electronic address: chmlifys@nus.edu.sg.
authors: Sam Fong Yau
authors: SF
authors: Li
mesh_terms: D055162:Biocatalysis; D002175:Candida / Q000201:enzymology; D002245:Carbon Dioxide / Q000737:chemistry* / Q000378:metabolism*; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005465:Fluorocarbon Polymers / Q000737:chemistry; D005560:Formate Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D005561:Formates / Q000378:metabolism; D055772:Green Chemistry Technology; D009243:NAD / Q000378:metabolism
chemical_list: D004800:Enzymes, Immobilized; D005465:Fluorocarbon Polymers; D005561:Formates; D009243:NAD; C030544:formic acid; D002245:Carbon Dioxide; C040402:perfluorosulfonic acid; D005560:Formate Dehydrogenases
keywords: Carbon dioxide reduction; Formate dehydrogenase; Formate synthesis; Nafion micelles; Neutral red