Redox-Polymer-Wired [NiFeSe] Hydrogenase Variants with Enhanced O Stability for Triple-Protected High-Current-Density H-Oxidation Bioanodes
Ruff, Adrian (Ruhr-University Bochum)
Szczesny, Julian (Ruhr-University Bochum)
Vega, Maria (Universitat Autònoma de Barcelona)
Zacarias, Sonia (Universidade NOVA de Lisboa)
Matias, Pedro M. (Instituto de Biologia Experimental e Tecnológica (iBET))
Gounel, Sébastien (Univ. Bordeaux)
Mano, Nicolas (Univ. Bordeaux)
Pereira, Inês A. C. (Universidade NOVA de Lisboa)
Schuhmann, Wolfgang (Ruhr-University Bochum)

Date:	2020
Abstract:	Variants of the highly active [NiFeSe] hydrogenase from D. vulgaris Hildenborough that exhibit enhanced O tolerance were used as H-oxidation catalysts in H/O biofuel cells. Two [NiFeSe] variants were electrically wired by means of low-potential viologen-modified redox polymers and evaluated with respect to H-oxidation and stability against O in the immobilized state. The two variants showed maximum current densities of (450±84) μA cm −2 for G491A and (476±172) μA cm −2 for variant G941S on glassy carbon electrodes and a higher O tolerance than the wild type. In addition, the polymer protected the enzyme from O damage and high-potential inactivation, establishing a triple protection for the bioanode. The use of gas-diffusion bioanodes provided current densities for H-oxidation of up to 6. 3 mA cm −2. Combination of the gas-diffusion bioanode with a bilirubin oxidase-based gas-diffusion O-reducing biocathode in a membrane-free biofuel cell under anode-limiting conditions showed unprecedented benchmark power densities of 4. 4 mW cm −2 at 0. 7 V and an open-circuit voltage of 1. 14 V even at moderate catalyst loadings, outperforming the previously reported system obtained with the [NiFeSe] wild type and the [NiFe] hydrogenase from D. vulgaris Miyazaki F. Triple protection : A stable, high-current-density-based H-oxidation bioanode is presented. It is equipped with [NiFeSe] variants that show enhanced O tolerance, which are immobilized and wired to electrode surfaces with a low-potential viologen-modified polymer. The polymer acts simultaneously as a high-potential and O shield. The triply protected bioanodes are incorporated in membrane-free biofuel cells, which reveal benchmark performances at moderate catalyst loading.
Grants:	Agencia Estatal de Investigación RTI2018-095090-B-I00 European Commission 810856
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Bioelectrocatalysis ; Biofuel cells ; Enzyme engineering ; Hydrogenases ; Redox polymers
Published in:	ChemSusChem, Vol. 13, Issue 14 (July 2020) , p. 3627-3635, ISSN 1864-564X

DOI: 10.1002/cssc.202000999
PMID: 32339386

9 p, 1.1 MB

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