Light-driven biohybrid system utilizes N2 for photochemical CO2 reduction

Light-driven biohybrid system was created for achieving effective photochemical CO2 reduction by utilizing abundant, atmospheric N-2 via biological nitrogen fixation to produce electron donors. Attempting to couple photochemical CO2 reduction with N-2 fixation is usually difficult, because the reaction conditions for these two processes are typically incompatible. Here, we report that a light-driven biohybrid system can utilize abundant, atmospheric N-2 to produce electron donors via biological nitrogen fixation, to achieve effective photochemical CO2 reduction. This biohybrid system is constructed by incorporating molecular cobalt-based photocatalysts into N-2-fixing bacteria. It is found that N-2-fixing bacteria can convert N-2 into reductive organic nitrogen and create a localized anaerobic environment, which allows the incorporated photocatalysts to continuously perform photocatalytic CO2 reduction under aerobic conditions. Specifically, the light-driven biohybrid system displays a high formic acid production rate of over 1.41 x 10(-14) mol h(-1) cell(-1) under visible light irradiation, and the organic nitrogen content undergoes an over-3-fold increase within 48 hours. This work offers a useful strategy for coupling CO2 conversion with N-2 fixation under mild and environmentally benign conditions.