(Keynote) Revisiting Protection Matrices for Bioelectrochemical Systems

Abstract

Redox hydrogel films are among the most practical approaches for protecting O2-sensitive biocatalysts such as hydrogenases from O2 inactivation in bioelectrochemical devices (1). Their protection mechanism relies on the viologen catalyzed reduction of O2 with electrons diverted from the hydrogenase catalyzed H2 oxidation. Despite multiple example of the versatility and universal applicability of the concept (1-3), numerous key question related to their practical use remain open. The lecture will cover unresolved points related to (i) the generation of reactive oxygen species, (ii) the use of excessive thicknesses to ensure protection as well as (iii) the elusive direct evidence for the protection mechanism. Recent progress in the ability to form films with controlled thicknesses (4) and the use of confocal fluorescence microscopy led to new exciting insights in these systems. (1) N. Plumeré, O. Rüdiger, A. Alsheikh Oughli, R. Williams, J. Vivekananthan, S. Pöller, W. Schuhmann, W. Lubitz, Nature Chemistry, 2014, 6, 822–827. (2) V. Fourmond, S. Stapf, H. Li, D. Buesen, J. Birrell, O. Rüdiger, W. Lubitz, W. Schuhmann, N. Plumeré, C. Léger, J. Am. Chem. Soc., 2015, 137, 5494-5505. (3) A. Alsheikh Oughli, F. Conzuelo, M. Winkler, T. Happe, W. Lubitz, W. Schuhmann, O. Rüdiger, N. Plumeré, Angew. Chem. Int. Ed., 2015, 54, 12329 –12333. (4) H. Li, D. Buesen, R Williams, J. Henig, S. Stapf, K. Mukherjee, E. Freier, W. Lubitz, M. Winkler, T. Happe, N. Plumeré, Chemical Science, 2018, 9, 7596-7605. Financial support by the Cluster of Excellence RESOLV (EXC 1069), by the ERC starting grant 715900 and by the ANR-DFG project SHIELDS (PL 746/2-1) is gratefully acknowledged.