Competition between electron transfer, trapping, and recombination in CdS nanorod–hydrogenase complexes

Utterback, James K.; Wilker, Molly B.; Brown, Katherine A.; King, Paul W.; Eaves, Joel D.; Duković, Gordana

doi:10.1039/c4cp05993j

Cited by 48 publications

(114 citation statements)

References 29 publications

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“…As hot e − relaxation in Cd-chalcogenide quantum dots occurs in the subpicosecond regime, this process does not likely contribute to the TA kinetics in the measured time scale (27). However, previous studies of FeFe H 2 ase-CdS constructs reported TA lifetimes in the range of 100 ns, significantly longer than the data presented here (19,20). The discrepancy may be attributed to the presence of surface ligands (not present in M. thermoaceticaCdS) which present a charge-transfer barrier, differences in CdS-H 2 ase spatial proximity, solvent effects and reorganization energies, H-bonding networks, and the relatively impaired functionality of purified enzymes under in vitro vs. in vivo conditions (28)(29)(30).…”

Section: −1contrasting

confidence: 54%

“…Membrane-bound NiFe H 2 ases may play a significant role as H 2 directly feeds into the WLP. Demonstrations of direct e − transfer between metal chalcogenide nanoparticles and purified H 2 ases in vitro lend credibility to this pathway's existence in complex whole cells (18)(19)(20). Alternative pathways have implicated e − transfer first to membrane-bound cytochromes, ferredoxin (Fd), flavoproteins (Fp), and menaquinones (MK) (13,14).…”

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confidence: 99%

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Spectroscopic elucidation of energy transfer in hybrid inorganic–biological organisms for solar-to-chemical production

Kornienko

Sakimoto

Herlihy

et al. 2016

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

156

126

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The rise of inorganic-biological hybrid organisms for solar-to-chemical production has spurred mechanistic investigations into the dynamics of the biotic-abiotic interface to drive the development of nextgeneration systems. The model system, Moorella thermoaceticacadmium sulfide (CdS), combines an inorganic semiconductor nanoparticle light harvester with an acetogenic bacterium to drive the photosynthetic reduction of CO 2 to acetic acid with high efficiency. In this work, we report insights into this unique electrotrophic behavior and propose a charge-transfer mechanism from CdS to M. thermoacetica. Transient absorption (TA) spectroscopy revealed that photoexcited electron transfer rates increase with increasing hydrogenase (H 2 ase) enzyme activity. On the same time scale as the TA spectroscopy, time-resolved infrared (TRIR) spectroscopy showed spectral changes in the 1,700-1,900-cm −1 spectral region. The quantum efficiency of this system for photosynthetic acetic acid generation also increased with increasing H 2 ase activity and shorter carrier lifetimes when averaged over the first 24 h of photosynthesis. However, within the initial 3 h of photosynthesis, the rate followed an opposite trend: The bacteria with the lowest H 2 ase activity photosynthesized acetic acid the fastest. These results suggest a two-pathway mechanism: a high quantum efficiency charge-transfer pathway to H 2 ase generating H 2 as a molecular intermediate that dominates at long time scales (24 h), and a direct energy-transducing enzymatic pathway responsible for acetic acid production at short time scales (3 h). This work represents a promising platform to utilize conventional spectroscopic methodology to extract insights from more complex biotic-abiotic hybrid systems.energy conversion | spectroscopy | CO 2 reduction | biohybrid systems | catalysis

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Section: −1contrasting

confidence: 54%

mentioning

confidence: 99%

Spectroscopic elucidation of energy transfer in hybrid inorganic–biological organisms for solar-to-chemical production

Kornienko

Sakimoto

Herlihy

et al. 2016

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

156

126

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“…For example, King et al. constructed a series of inorganic‐biological hybrid systems using cadmium telluride (CdTe) or cadmium sulfide (CdS) nanorods and purified [FeFe]‐hydrogenase derived from Clostridium acetobutylicum [3a–d] . These systems showed the performance of highly active [FeFe]‐hydrogenase [4] and achieved highly efficient light‐driven hydrogen production; however, difficulties owing to the high costs of protein purification and the high oxygen sensitivity of [FeFe]‐hydrogenase must be addressed for further improvement of these systems.…”

Section: Introductionmentioning

confidence: 99%

Photo‐biohydrogen Production by Photosensitization with Biologically Precipitated Cadmium Sulfide in Hydrogen‐Forming Recombinant Escherichia coli

et al. 2020

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An inorganic-biological hybrid system that integrates features of both stable and efficient semiconductors and selective and efficient enzymes is attractive for facilitating the conversion of solar energy to hydrogen. In this study, we aimed to develop a new photocatalytic hydrogen-production system based on Escherichia coli whole-cell genetically engineered as a biocatalysis for highly active hydrogen formation. The photocatalysis part was obtained by bacterial precipitation of cadmium sulfide (CdS), which is a visible-light-responsive semiconductor. The recombinant E. coli cells were sequentially subjected to CdS precipitation and heterologous [FeFe]-hydrogenase synthesis to yield a CdS@E. coli hybrid capable of light energy conversion and hydrogen formation in a single cell. The CdS@E. coli hybrid achieved photocatalytic hydrogen production with a sacrificial electron donor, thus demonstrating the feasibility of our system and expanding the current knowledge of photosensitization using a whole-cell biocatalyst with a bacterially precipitated semiconductor.

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“…Using longer capping ligands resulted in less-efficient hydrogenase adsorption and slower electron transfer, resulting in an overall decrease in hydrogen production. A recurring theme in enzyme-nanocrystal hybrids is the critical impact of efficient and directed electron transfer on hydrogen production, where controlling ratios between enzymes and nanocrystals and selecting capping ligands that facilitate optimal nanocrystalenzyme association play key roles [137]. This high degree of tunability could be powerful in shaping the future of lightdriven enzyme catalysis, especially because enzymes can also be tuned to facilitate interactions with nanoparticles by altering surface residues around key electron transfer sites.…”

Section: Figmentioning

confidence: 99%

Light‐driven catalysis with engineered enzymes and biomimetic systems

Edwards

Bren

2020

Biotech and App Biochem

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Efforts to drive catalytic reactions with light, inspired by natural processes like photosynthesis, have a long history and have seen significant recent growth. Successfully engineering systems using biomolecular and bioinspired catalysts to carry out light‐driven chemical reactions capitalizes on advantages offered from the fields of biocatalysis and photocatalysis. In particular, driving reactions under mild conditions and in water, in which enzymes are operative, using sunlight as a renewable energy source yield environmentally friendly systems. Furthermore, using enzymes and bioinspired systems can take advantage of the high efficiency and specificity of biocatalysts. There are many challenges to overcome to fully capitalize on the potential of light‐driven biocatalysis. In this mini‐review, we discuss examples of enzymes and engineered biomolecular catalysts that are activated via electron transfer from a photosensitizer in a photocatalytic system. We place an emphasis on selected forefront chemical reactions of high interest, including CH oxidation, proton reduction, water oxidation, CO2 reduction, and N2 reduction.

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Competition between electron transfer, trapping, and recombination in CdS nanorod–hydrogenase complexes

Cited by 48 publications

References 29 publications

Spectroscopic elucidation of energy transfer in hybrid inorganic–biological organisms for solar-to-chemical production

Spectroscopic elucidation of energy transfer in hybrid inorganic–biological organisms for solar-to-chemical production

Photo‐biohydrogen Production by Photosensitization with Biologically Precipitated Cadmium Sulfide in Hydrogen‐Forming Recombinant Escherichia coli

Light‐driven catalysis with engineered enzymes and biomimetic systems

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