Semiconducting Mineral Photocatalytic Regeneration of Fe2+ Promotes Carbon Dioxide Acquisition by Acidithiobacillus ferrooxidans

Chemoautotrophic organisms have once been excluded from the development of universally applicable CO₂ fixation technology due to its low production yields of biomass. In this study, we used Acidithiobacillus ferrooxidans (A.f.) as a model chemoautotrophic microorganism to test the hypothesis that exogenetic photoelectrons from semiconducting mineral photocatalysis can enable the regeneration of Fe²⁺ that could be then used by A.f. and support its growth. In a simulated electrochemical system, where exogenetic electrons were provided by an electrochemical approach, an accelerated growth rate of A.f. was observed as compared with that in traditional batch cultivation. In a coupled system, where light‐irradiated natural rutile provided the primary electron source to feed A.f., the bacterial growth rate as well as the subsequent CO₂ fixation rate was demonstrated to be in a light‐dependent manner. The sustaining flow of photogenerated electrons from semiconducting mineral to bacteria provided an inexhaustible electron source for chemoautotrophic bacteria growth and CO₂ fixation. This finding might contribute to the development of novel effective CO₂ fixation technology.