Fig. 1.

Hybrid photosynthesis with photovoltaic cell. a PV-driven MES or EE. In the first MES-based example, R. eutropha oxidized H₂ generated at the cathode to reduce CO₂ into PHB and/or C3 and C5 alcohols [77]. In the second EE-based example, the reduction of CO₂ into formate by a formate dehydrogenase via NADH and neutral red (NR) could be powered by a PV cell [108–110, 112]. No membrane was present between the electrodes in the first example, while in the second example, either an ion-exchange membrane (IEM) or salt bridge was present. b Alternatively, PV can power H₂ evolution by an electrolyzer. H₂ can then be mixed with CO₂ and fed to a gas bioreactor. Here, a polymer electrolyte membrane (PEM) electrolyzer is depicted