Immobilized Enzymes on Graphene as Nanobiocatalyst

Abstract

Using enzymes as bioelectrocatalysts is an important step toward the next level of biotechnology for energy production. In such biocatalysts, a sacrificial cofactor as an electron and proton source is needed. This is a great obstacle for upscaling, due to cofactor instability and product separation issues, which increase the costs. Here, we report a cofactor-free electroreduction of CO2 to a high energy density chemical (methanol) catalyzed by enzyme–graphene hybrids. The biocatalyst consists of dehydrogenases covalently bound on a well-defined carboxyl graphene derivative, serving the role of a conductive nanoplatform. This nanobiocatalyst achieves reduction of CO2 to methanol at high current densities, which remain unchanged for at least 20 h of operation, without production of other soluble byproducts. It is thus shown that critical improvements on the stability and rate of methanol production at a high Faradaic efficiency of 12% are possible, due to the effective electrochemical process from the electrode to the enzymes via the graphene platform.

Human virus detection with graphene-based materials

“…Graphene acid is a conductive graphene derivative with a well-defined chemistry, as both sides of graphene are densely (with ~15% degree of functionalization) and homogenously decorated by carboxyl groups ( Bakandritsos et al, 2017 ). The carboxyl groups of graphene acid enable efficient covalent enzyme immobilization ( Seelajaroen et al, 2020 ), which can be exploited in electrochemical sensing in the future.…”

Sustainable Carbon Materials toward Emerging Applications

“…[ 172 ] In comparison to noble metals, carbon nanomaterials display the advantages for biosensing due to following three aspects: 1) the carbon nanomaterials are more cost‐effective than noble metals (carbon of ≈$ 0.03 per gram, Au of ≈$60 per gram/Ag of ≈$25 per gram/Pt of ≈$34 per gram); [ 173,174 ] 2) the carbon nanomaterials are obtained from plentiful raw materials especially sustainable biomass materials, superior to the noble metals with limited source; 3) the carbon nanomaterials are prepared with uniformity and structural diversity, while preparing noble metals with controllable composition and structures have been still limited. [ 175–177 ] Specifically, the classical carbon materials own high thermal/electrical conductivity and immense derivatization capability, [ 178,179 ] thus supporting molecule (e.g., peptide [ 180 ] ) and cell detection. [ 181,182 ] The carbon hybrid materials, that carbon materials are doped with other elements, display good biocompatibility, abundant catalytic sites and high thermal/chemical stability for diagnostic and therapeutic applications.…”

CO2 Recycling: The Conversion of Renewable Energy into Chemical Fuels

“…Ve r y r e c e n t l y H a t h a i c h a n o k Seelajeroen et al demonstrated the immobilization of three different enzymes on a functionalized graphene. 16 In these nano-bio-catalysts we used graphene as electrical platform to hook three different enzymes thereon and perform the biocatalysis from CO 2 over formate over formaldehyde all the way to methanol (see Fig. 13).…”

“…Reproduced with permission from reference 15 . Figure 13: Schematic description of electrically addressing three different enzymes immobilized on a functionalized graphene sheet as described in reference 16 .…”