Beyond Natural Synthesis via Solar-Decoupled Biohybrid Photosynthetic System
Academic Background
Photosynthetic microorganisms can directly convert carbon dioxide (CO₂) into high value-added long-chain chemicals by converting solar energy into chemical energy, providing a promising route for CO₂ sequestration and sustainable development. However, the key reducing power generated in photosynthetic reactions—nicotinamide adenine dinucleotide phosphate (NADPH)—is mainly used to support microbial survival in the dark rather than for biosynthesis. This limitation seriously restricts the practical potential of photosynthetic microbes. To address this issue, researchers have proposed a solar-decoupled biohybrid strategy, in which a persistent photocatalyst is combined with photosynthetic microbes, thereby decoupling the light and dark reactions and enabling the continuous utilization of CO₂ and the biosynthesis of long-chain chemicals under light-free conditions.
Paper Source
This paper was jointly written by Na Chen, Jing Xi, Tianpei He, and other authors from Renmin Hospital of Wuhan University, Hunan University, Shanghai Jiao Tong University, and other institutions. The paper was published in Chem on April 10, 2025, with the title “Beyond Natural Synthesis via Solar-Decoupled Biohybrid Photosynthetic System.” The corresponding authors are Lilei Yu, Yun Zhang, and Quan Yuan.
Research Process and Results
1. Research Design
The research team proposed a solar-decoupled biohybrid strategy, which combines a persistent photocatalyst with photosynthetic microorganisms (such as Rhodopseudomonas palustris) to achieve the decoupling of light and dark reactions. The persistent photocatalyst can collect and store photo-generated charges during periods of illumination and slowly release them under darkness, thereby providing a continuous source of reducing power to the microorganisms.
2. Photocatalyst Design and Optimization
The team adopted Zn1.2Ga1.6Ge0.2O4 (ZGG0) as the persistent photocatalyst and introduced defect engineering via nickel (Ni) doping to improve its solar energy storage efficiency. Through density functional theory (DFT) calculations and experimental validation, the researchers found that Ni doping could optimize the electronic structure of the catalyst, reduce the band gap, and increase the number of oxygen vacancies (Vo) and germanium vacancies (VGe), thus significantly enhancing the hydrogen storage efficiency of the photocatalyst.
3. Construction of the Biohybrid System
The researchers combined the optimized ZGG0:Ni photocatalyst with R. palustris to construct the solar-decoupled biohybrid system. Experiments showed that the photocatalyst could convert solar energy into reducing hydrogen (H₂) and photoelectrons during illumination and slowly release these reducing equivalents in the dark, thereby driving microbial NADPH regeneration and biosynthesis processes.
4. Experimental Results
- Photocatalytic Efficiency: The apparent photo conversion efficiency (APCE) of the ZGG0:Ni photocatalyst reached 8.30%, significantly higher than the control group without the photocatalyst (4.36%).
- NADPH Regeneration: Under dark conditions, the reducing power stored in the photocatalyst could significantly improve the NADPH regeneration efficiency of the microorganisms, ultimately reaching 36.30%.
- CO₂ Fixation and Biosynthesis: The CO₂ fixation rate and lycopene yield of the biohybrid system reached 3.17 mM/g DCW/h and 8.80 mg/L, respectively, both significantly higher than those of the control group.
5. Molecular Mechanism Analysis
Through transcriptomic and metabolomic analyses, the researchers found that the photocatalyst significantly upregulated the gene expression associated with electron transfer, photosynthesis, the Calvin-Benson-Bassham (CBB) cycle, and hydrogenases, thereby enhancing the metabolic activity of the microorganisms.
Conclusion and Significance
This study successfully achieved the goal of continuous CO₂ utilization and efficient biosynthesis in the absence of light by constructing a solar-decoupled biohybrid system. This strategy not only significantly improved the solar energy utilization efficiency of photosynthetic microbes but also provided new ideas for sustainable energy storage and utilization. In addition, the study demonstrated the potential of the biohybrid system in industrial applications, such as coupling with thermal power plants for CO₂ capture and utilization.
Research Highlights
- Innovative Strategy: Proposed a solar-decoupled biohybrid strategy that achieves the decoupling of light and dark reactions by integrating persistent photocatalysts with photosynthetic microorganisms.
- Highly Efficient Photocatalyst: The hydrogen storage efficiency and solar energy conversion efficiency of the photocatalyst were significantly improved through defect engineering and Ni doping.
- Broad Applicability: The strategy is not only applicable to R. palustris but also to other photosynthetic microorganisms, such as Synechocystis, demonstrating its broad applicability.
- Industrial Application Potential: This research provides a new technological route for CO₂ capture and utilization, and is of important industrial application value.
Other Valuable Information
The researchers also validated the environmental and economic advantages of the biohybrid system through life cycle assessment (LCA), showing it can significantly reduce greenhouse gas emissions and energy consumption, while lowering production costs. In addition, the research team explored the potential of the system in extreme environments (such as space), further extending its application scenarios.
This study, through its innovative biohybrid strategy, provides a new technological pathway for sustainable energy utilization and CO₂ sequestration, possessing significant scientific value and practical application potential.