Thylakoid Membrane-Inspired Capsules with Fortified Cofactor Shuttling for Enzyme-Photocoupled Catalysis

Abstract

Enzyme-photocoupled catalytic systems (EPCSs), combining the natural enzyme with a library of semiconductor photocatalysts, may break the constraint of natural evolution, realizing sustainable solar-to-chemical conversion and non-natural reactivity of the enzyme. The overall efficiency of EPCSs strongly relies on the shuttling of energy-carrying molecules, e.g., NAD+/NADH cofactor, between active centers of enzyme and photocatalyst. However, few efforts have been devoted to NAD+/NADH shuttling. Herein, we propose a strategy of constructing a thylakoid membrane-inspired capsule (TMC) with fortified and tunable NAD+/NADH shuttling to boost the enzyme-photocoupled catalytic process. The apparent shuttling number (ASN) of NAD+/NADH for TMC could reach 17.1, ∼8 times as high as that of non-integrated EPCS. Accordingly, our TMC exhibits a turnover frequency (TOF) of 38 000 ± 365 h–1 with a solar-to-chemical efficiency (STC) of 0.69 ± 0.12%, ∼6 times higher than that of non-integrated EPCS.

Bioinspired Metalation of the Metal‐Organic Framework MIL‐125‐NH2 for Photocatalytic NADH Regeneration and Gas‐Liquid‐Solid Three‐Phase Enzymatic CO2 Reduction

“…The decreased PL intensity of (MIL-125-Py-Rh) 0.05 implies the prohibited electron-hole recombination and the enhanced electron transfer behavior. [16] This can also be confirmed by the photocurrent performance in Figure S11. (MIL-125-Py-Rh) 0.05 exhibited a higher photocurrent density than those of MIL-125-NH 2 and (MIL-125-Py) 0.05 , which indicated the enhanced electron transfer through Rh immobilization.…”

“…(MIL-125-Py-Rh) 0.05 had a longer carrier average lifetime (0.46 ns) than those of MIL-125-NH 2 (0.32 ns) and (MIL-125-Py) 0.05 (0.33 ns), indicating that Rh could increase the photoelectron lifetime of (MIL-125-Py-Rh) 0.05 and then lead to a more efficient transfer of photogenerated electrons. [16] Based on above findings, the (MIL-125-Py-Rh) x was proposed as a novel photocatalyst for NADH regeneration upon light illumination. In a typical experiment, the system included phosphate buffer (pH = 7.4), photocatalyst (5 mg mL À 1 ), NAD + (1 mmol L À 1 ), blue LED illumination and triethanolamine.…”

“…[10][11][12] Over the years, various methods have been developed to regenerate NADH, including enzymatic, chemical, electrochemical and photocatalytic routes. [13][14][15][16] Among them, light-driven NADH regeneration, featuring green, economic and sustainable nature, has aroused great attention recently. Inspired by natural photosynthesis, the coupling of photocatalytic NADH regeneration with the bioenzymatic CO 2 reduction could serve the purpose of fine chemicals production utilizing solar energy.…”

“…Especially, by further immobilizing the enzyme, constructing the recyclable synthetic materials-enzyme hybrids as the semi-artificial photosynthetic system for CO 2 reduction is very promising for sustained commercial applications in solar energy conversion. [16][17][18] Photocatalytic NADH regeneration usually occurs in the presence of photocatalysts as well as homogeneous metal complex (such as [Cp*Rh(bpy)H 2 O] 2 + ), which act as the electron and proton mediator. [19][20][21][22][23][24][25] Previously, most of the photoinduced electrons were transferred from the heterogeneous semiconductor particles to the homogeneous Rh complex to accomplish the first step of the photocatalytic NADH regeneration, which could pose severe electron transfer loss.…”

“…Such process usually requires the stoichiometric consumption of NADH for sustained CO 2 reduction, which necessitates the regeneration of NADH [10‐12] . Over the years, various methods have been developed to regenerate NADH, including enzymatic, chemical, electrochemical and photocatalytic routes [13‐16] . Among them, light‐driven NADH regeneration, featuring green, economic and sustainable nature, has aroused great attention recently.…”