An electrochemically functional layer of hydrogenase extract on an electrode of large and tunable specific surface area

Schlicht, Stefanie; Assaud, Loïc; Hansen, M.; Licklederer, Markus; Bechelany, Mikhaël; Perner, Mirjam; Bachmann, Julien

doi:10.1039/c6ta00392c

Cited by 19 publications

(15 citation statements)

References 61 publications

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“…Hydrogen-converting enzymes are of particular interest for the use in hydrogen production as a clean energy carrier and energy generation in biofuel cells ( Armstrong et al, 2009 ; Chenevier et al, 2013 ). As shown for Escherichia coli ’s hydrogenases for example, these enzymes can be used for enhanced hydrogen production on surface-enlarged nanofiber electrodes ( Schlicht et al, 2016 ). Due to the steep thermal and chemical gradients prevailing in vent environments, enzymes of exceptional stability under various conditions (e.g., temperature or oxygen contents) can be expected to be found.…”

Section: Accessing the Uncultured Majority And Their Hydrogen-convertmentioning

confidence: 99%

Microbially Mediated Hydrogen Cycling in Deep-Sea Hydrothermal Vents

Adam

Perner

2018

Front. Microbiol.

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Deep-sea hydrothermal vents may provide one of the largest reservoirs on Earth for hydrogen-oxidizing microorganisms. Depending on the type of geological setting, hydrothermal environments can be considerably enriched in hydrogen (up to millimolar concentrations). As hot, reduced hydrothermal fluids ascend to the seafloor they mix with entrained cold, oxygenated seawater, forming thermal and chemical gradients along their fluid pathways. Consequently, in these thermally and chemically dynamic habitats biochemically distinct hydrogenases (adapted to various temperature regimes, oxygen and hydrogen concentrations) from physiologically and phylogenetically diverse Bacteria and Archaea can be expected. Hydrogen oxidation is one of the important inorganic energy sources in these habitats, capable of providing relatively large amounts of energy (237 kJ/mol H2) for driving ATP synthesis and autotrophic CO2 fixation. Therefore, hydrogen-oxidizing organisms play a key role in deep-sea hydrothermal vent ecosystems as they can be considerably involved in light-independent primary biomass production. So far, the specific role of hydrogen-utilizing microorganisms in deep-sea hydrothermal ecosystems has been investigated by isolating hydrogen-oxidizers, measuring hydrogen consumption (ex situ), studying hydrogenase gene distribution and more recently by analyzing metatranscriptomic and metaproteomic data. Here we summarize this available knowledge and discuss the advent of new techniques for the identification of novel hydrogen-uptake and -evolving enzymes from hydrothermal vent microorganisms.

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Section: Accessing the Uncultured Majority And Their Hydrogen-convertmentioning

confidence: 99%

Microbially Mediated Hydrogen Cycling in Deep-Sea Hydrothermal Vents

Adam

Perner

2018

Front. Microbiol.

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“…The frequency-dependent resistance arises from the capacitance C e (as 1/ωC): it reflects engagement of the cyclic contribution from reversible chemical steps ranging from binding/release of H 2 to atom/ion transfer, as well as electron transfers that are tightly coupled to these steps (30,31). Expressed another way, R e represents the DC resistance always offered by the combined electron relay and active site, whereas C e is analogous to a time-dependent charging and discharging of the active site (this is a Faradaic process because catalytic cycling allows electrons to flow).…”

Section: Electrochemical Impedance Spectroscopymentioning

confidence: 99%

Frequency and potential dependence of reversible electrocatalytic hydrogen interconversion by [FeFe]-hydrogenases

Pandey

Islam

Happe

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The kinetics of hydrogen oxidation and evolution by [FeFe]hydrogenases have been investigated by electrochemical impedance spectroscopy-resolving factors that determine the exceptional activity of these enzymes, and introducing an unusual and powerful way of analyzing their catalytic electron transport properties. Attached to an electrode, hydrogenases display reversible electrocatalytic behavior close to the 2H + /H 2 potential, making them paradigms for efficiency: the electrocatalytic "exchange" rate (measured around zero driving force) is therefore an unusual parameter with theoretical and practical significance. Experiments were carried out on two [FeFe]-hydrogenases, CrHydA1 from the green alga Chlamydomonas reinhardtii, which contains only the active-site "H cluster," and CpI from the fermentative anaerobe Clostridium pasteurianum, which contains four low-potential FeS clusters that serve as an electron relay in addition to the H cluster. Data analysis yields catalytic exchange rates (at the formal 2H + /H 2 potential, at 0°C) of 157 electrons (78 molecules H 2 ) per second for CpI and 25 electrons (12 molecules H 2 ) per second for CrHydA1. The experiments show how the potential dependence of catalytic electron flow comprises frequency-dependent and frequency-independent terms that reflect the proficiencies of the catalytic site and the electron transfer pathway in each enzyme. The results highlight the "wire-like" behavior of the Fe-S electron relay in CpI and a low reorganization energy for electron transfer on/off the H cluster.hydrogen | electrocatalysis | impedance spectroscopy | hydrogenase | electron transfer

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“…All depositions have been carried out in a custom-built ALD reactor described elsewhere [ 33 ]. Titanium isopropoxide (( i PrO) 4 Ti) precursor was purchased from Sigma Aldrich and used as received.…”

Section: Methodsmentioning

confidence: 99%

“…This result is in agreement with previous studies that showed that TiO 2 films deposited by ALD below 200 °C are amorphous, and that annealing at temperatures above 300 °C are typically required to obtain the crystallization of the films. Crystalline TiO 2 typically exhibits the anatase phase, but the rutile phase can also be achieved by ALD, using ozone or plasmas as coreactants [ 33 , 35 , 36 ]. The relative density of the ALD TiO 2 has been reported elsewhere to be 3.6 g/cm 3 [ 37 ].…”

Section: Methodsmentioning

confidence: 99%

Low-Coherence Interferometric Fiber-Optic Sensors with Potential Applications as Biosensors

Hirsch

Majchrowicz

Wierzba

et al. 2017

Sensors

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Fiber-optic Fabry-Pérot interferometers (FPI) can be applied as optical sensors, and excellent measurement sensitivity can be obtained by fine-tuning the interferometer design. In this work, we evaluate the ability of selected dielectric thin films to optimize the reflectivity of the Fabry-Pérot cavity. The spectral reflectance and transmittance of dielectric films made of titanium dioxide (TiO 2 ) and aluminum oxide (Al 2 O 3 ) with thicknesses from 30 to 220 nm have been evaluated numerically and compared. TiO 2 films were found to be the most promising candidates for the tuning of FPI reflectivity. In order to verify and illustrate the results of modelling, TiO 2 films with the thickness of 80 nm have been deposited on the tip of a single-mode optical fiber by atomic layer deposition (ALD). The thickness, the structure, and the chemical properties of the films have been determined. The ability of the selected TiO 2 films to modify the reflectivity of the Fabry-Pérot cavity, to provide protection of the fibers from aggressive environments, and to create multi-cavity interferometric sensors in FPI has then been studied. The presented sensor exhibits an ability to measure refractive index in the range close to that of silica glass fiber, where sensors without reflective films do not work, as was demonstrated by the measurement of the refractive index of benzene. This opens up the prospects of applying the investigated sensor in biosensing, which we confirmed by measuring the refractive index of hemoglobin and glucose.

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An electrochemically functional layer of hydrogenase extract on an electrode of large and tunable specific surface area

Abstract: International audienc

Cited by 19 publications

References 61 publications

Microbially Mediated Hydrogen Cycling in Deep-Sea Hydrothermal Vents

Microbially Mediated Hydrogen Cycling in Deep-Sea Hydrothermal Vents

Frequency and potential dependence of reversible electrocatalytic hydrogen interconversion by [FeFe]-hydrogenases

Low-Coherence Interferometric Fiber-Optic Sensors with Potential Applications as Biosensors

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