Semiconducting Mineral Photocatalytic Regeneration of Fe 2+ Promotes Carbon Dioxide Acquisition by Acidithiobacillus ferrooxidans

Chemoautotrophic organisms have once been excluded from the development of universally applicable CO 2 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 Fe 2+ 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 CO 2 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 CO 2 fixation. This finding might contribute to the development of novel effective CO 2 fixation technology.