The harmonious coexistence between the human society and the nature has prompted the rapid development of advanced manufacturing. Typically, green biomanufacturing, which uses renewable resources as raw materials and enzymes or microorganisms as catalysts to produce target chemicals, has been considered to be highly consistent with The Twelve Principles of Green Chemistry. Specifically, enzyme-based green biomanufacturing has been extensively applied for many industrial fields such as food, pharmaceutical, chemicals, etc. Reduction reactions are most commonly employed in enzyme-based biomanufacturing processes. The continuous supply of reducing energy is therefore essential. Introducing fossil energy is the frequently used strategy, which does not only cause the increase of production costs, but also lead to the generation of oxidation by-products that are difficult to separate. Therefore, using cheap and renewable energy (such solar energy) to afford sufficient reducing energy is urgently required for achieving sustainable green biomanufacturing.
Natural photosynthesis offers an ideal prototype of green biomanufacturing, during which green plants absorb sunlight and split H2O into O2, electrons and protons. These electrons and protons are used to drive the synthesis of energy-rich biological reductants, such as NADPH and ATP, which are further involved in the Calvin-Benson cycle to accomplish the CO2 fixation.
Enzyme-Photo-coupled Catalytic System (EPCS) is a typical solar-driven biomanufacturing process. EPCS, as a new model to mimic natural photosynthesis, can use photocatalysts to capture solar energy and further drive the enzyme catalysis for the production of various chemicals. However, the solar-to-chemical conversion efficiency of EPCS is far below theoretical upper limit for the photosynthesis in nature. Conventional EPCS focuses on the development of photocatalysts or the matching between photocatalysts and enzymes, while never offers guidelines for the construction of EPCS from the perspective of molecule-electron-proton transfer.
Recently, a research team led by Prof. Zhongyi Jiang from Tianjin University, China proposed a new strategy to strengthen the mass/energy coupling in EPCS by coordinating and optimizing the "New Three Transfers" (molecule, electron and proton transfer), thus improving the solar-to-chemical conversion efficiency. Natural photosynthesis provides an ideal model with well-matched molecule-electron-proton transfer, which would help to shed light on the molecule-electron-proton transfer phenomenon in EPCS. This review aimed to implant the molecule-electron-proton transfer from natural photosynthesis to EPCS. In addition, the current status and grand challenges in realizing the synergistic intensification of all three transfers in EPCS were analyzed, and some perspectives on research and development of EPCS were offered. The review was published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(22)64154-8).
