Solar Fuel Synthesis Using a Semiartificial Colloidal Z-Scheme.

The integration of enzymes with semiconductor light absorbers in semiartificial photosynthetic assemblies offers an emerging strategy for solar fuel production. However, such colloidal biohybrid systems rely currently on sacrificial reagents, and semiconductor-enzyme powder systems that couple fuel production to water oxidation are therefore needed to mimic an overall photosynthetic reaction. Here, we present a Z-scheme colloidal enzyme system that produces fuel with electrons sourced from water.

Electro-enzymatic ATP regeneration coupled to biocatalytic phosphorylation reactions.

Adenosine-5-triphosphate (ATP) is the main energy vector in biological systems, thus its regeneration is an important issue for the application of many enzymes of interest in biocatalysis and synthetic biology. We have developed an electroenzymatic ATP regeneration system consisting in a gold electrode modified with a floating phospholipid bilayer that allows coupling the catalytic activity of two membrane-bound enzymes: NiFeSe hydrogenase from Desulfovibrio vulgaris and FF-ATP synthase from Escherichia coli. Thus, H is used as a fuel for producing ATP.

Understanding the local chemical environment of bioelectrocatalysis.

Bioelectrochemistry employs an array of high-surface-area meso- and macroporous electrode architectures to increase protein loading and the electrochemical current response. While the local chemical environment has been studied in small-molecule and heterogenous electrocatalysis, conditions in enzyme electrochemistry are still commonly established based on bulk solution assays, without appropriate consideration of the nonequilibrium conditions of the confined electrode space. Here, we apply electrochemical and computational techniques to explore the local environment of fuel-producing oxidoreductases within porous electrode architectures.

A Semi-artificial Photoelectrochemical Tandem Leaf with a CO -to-Formate Efficiency Approaching 1 .

Semi-artificial photoelectrochemistry can combine state-of-the-art photovoltaic light-absorbers with enzymes evolved for selective fuel-forming reactions such as CO reduction, but the overall performance of such hybrid systems has been limited to date. Here, the electrolyte constituents were first tuned to establish an optimal local environment for a W-formate dehydrogenase to perform electrocatalysis. The CO reductase was then interfaced with a triple cation lead mixed-halide perovskite through a hierarchically structured porous TiO scaffold to produce an integrated photocathode achieving a photocurrent density of -5 mA cm at 0.