关键词: 生物光伏, 光合电子传递, 跨膜电子传递, 合成微生物组

Abstract:

Biophotovoltaics (BPV) is an environmentally friendly power generation technology that uses self-renewing photosynthetic microorganisms to absorb solar energy and convert it into electricity. BPV is an energy transduction process that involves photochemical reactions occurring in photosynthetic cells, extracellular electron transfer occurring at cell-electrode interfaces, and electrical current generation occurring in bioelectrochemical systems. However, the intrinsic light-dependent exoelectrogenic activity of photosynthetic microorganisms is extremely weak, which hampers the electrical outputs of BPV systems. In recent years, different electron transfer strategies have been developed to more efficiently extract photosynthetic electrons. These include the exogenous electron mediators-based strategy, conductive nanomaterials-based strategy, and synthetic microbial consortia-based strategy. Among them, the exogenous electron mediators-based strategy could improve the instantaneous efficiency; however, the improvement tends to be unstable. The conductive nanomaterials-based strategy can hardly achieve a targeted distribution of nanomaterials, and the cost of nanomaterials is also an issue. The synthetic microbial consortia-based strategy shows great potential in enhancing the power output and prolonging the lifetime of BPV systems. This review gives an overview of the development history of BPV technology, and summarizes the fundamental principles, advantages, and disadvantages of different strategies for electron extraction. Moreover, we also discuss different biotic/abiotic approaches that have been taken to improve the electrical outputs of BPV systems. These approaches mainly include broadening available photosynthetic materials, remolding intracellular metabolism and electron transfer, developing advanced electrodes with new materials and structures, and designing high-performance devices with novel configurations. Furthermore, we envision the real-world applications of BPV technology in the future, e.g., running small electronic sensors on environmental and agricultural internet of things, driving hydrogen production, and even being applied in space scientific research. To this end, the scale-up of BPV systems is required to amplify the output voltage and output power. Lastly, we propose that it is crucial to understand the molecular mechanisms behind the exoelectrogenesis of photosynthetic microorganisms in order to facilitate the advancement of BPV technology. One possible approach is to utilize synthetic biology to reconstruct transmembrane molecular wires using multi-heme cytochromes or nanowires.

Key words: biophotovoltaics, photosynthetic electron transfer, extracellular electron transfer, synthetic microbial consortia