Bioelectrocatalytic Activity of W-Formate Dehydrogenase Covalently Immobilized on Functionalized Gold and Graphite Electrodes

Abstract

The decrease of greenhouse gases such as CO 2 has become a key challenge for the human kind and the study of the electrocatalytic properties of CO 2 -reducing enzymes such as formate dehydrogenases is of importance for this goal. In this work, we study the covalent bonding of Desulfovibrio vulgaris Hildenborough FdhAB formate dehydrogenase to chemically modified gold and low-density graphite electrodes, using electrostatic interactions for favoring oriented immobilization of the enzyme. Electrochemical measurements show both bioelectrocatalytic oxidation of formate and reduction of CO 2 by direct electron transfer (DET). Atomic force microscopy and quartz crystal microbalance characterization, as well as a comparison of direct and mediated electrocatalysis, suggest that a compact layer of formate dehydrogenase was anchored to the electrode surface with some crosslinked aggregates. Furthermore, the operational stability for CO 2 electroreduction to formate by DET is shown with approximately 100% Faradaic yield.

Improving the Enzymatic Cascade of Reactions for the Reduction of CO2 to CH3OH in Water: From Enzymes Immobilization Strategies to Cofactor Regeneration and Cofactor Suppression

“…Finally, we also reported the case of Alvarez-Malmagro et al, who studied the reduction of CO 2 to formate by direct electron transfer to Formate dehydrogenase from Desulfovibrio vulgaris chemically immobilized on modified gold and low-density graphite electrodes, achieving a formate yield of 3.5 µM and a faradaic efficiency of about 100% [ 61 ].…”

“…enzyme: [Formate] = 3.7 µM. Faradaic efficiencies of around 100% No NADH but direct electron transfer [ 61 ] …”

“…Other special cases are those in which enzymes are immobilized on electrodes, for example, the experiments carried out by Schlager [ 51 ], Seelajaroen [ 58 ], and Alvarez-Malmagro [ 61 ]. The interest in the latter type of support stems from the idea of eliminating the need for a cofactor which, as discussed above, is a limiting factor in the reaction.…”

Electrochemical Studies of CO2‐Reducing Metalloenzymes

“…Alvarez‐Malmagro and co‐workers also recently showed efficient CO 2 electroreduction by using Dv FdhAB covalently immobilized on low‐density graphite (LDG) electrodes, with MV as a mediator [107] . Interestingly, the enzyme worked also in direct electron transfer (DET) because the electrodes were modified with amino groups, suitable for the covalent attachment of FDH with an orientation favorable for DET (most exposed [4Fe4S] cluster facing the electrode surface).…”

Engineering Electro- and Photocatalytic Carbon Materials for CO2 Reduction by Formate Dehydrogenase

“…29,30 The immobilization of enzymes on modified electrodes (Figure 1a,b) 31 provides an electrochemical tool to probe the activity of enzyme films (catalytic current) as a function of applied potential, material surface chemistry, and external chemical components (buffers, SEDs, redox mediators), which can guide the improvement in the performance of a photocatalytic support with an analogous surface. W-FDH from DvH has previously displayed DET activity on positively charged amine-modified graphite 32 and Au 33 electrodes, but an in-depth understanding of the enzyme−electrode interface and the extension of this observation to photocatalytic materials have not yet been reported (Figure 1a,c).…”