Photosynthetic semiconductor biohybrids for solar-driven biocatalysis

Photosynthetic semiconductor biohybrids integrate the best attributes of biological whole-cell catalysts and semiconducting nanomaterials. Enzymatic machinery enveloped in its native cellular environment offers exquisite product selectivity and low substrate activation barriers while semiconducting nanomaterials harvest light energy stably and efficiently. In this Review Article, we illustrate the evolution and advances of photosynthetic semiconductor biohybrids focusing on the conversion of CO2 to value-added chemicals. We begin by considering the potential of this nascent field to meet global energy challenges while comparing it to alternate approaches. This is followed by a discussion of the advantageous coupling of electrotrophic organisms with light-active electrodes for solar-to-chemical conversion. We detail the dynamic investigation of photosensitized microorganisms creating direct light harvesting within unicellular organisms while describing complementary developments in the understanding of charge transfer mechanisms and cytoprotection. Lastly, we focus on trends and improvements needed in photosynthetic semiconductor biohybrids in order to address future challenges and enhance their widespread adoption for the production of solar chemicals. Artificial photosynthetic technologies could potentially contribute to limiting global warming while providing useful chemicals for society. This Review Article covers photosynthetic semiconductor biohybrids-electrodes/nanomaterials coupled with microorganisms-for light-driven catalytic conversion of CO2 to fuels and other value-added chemicals.