Acetogenic bacteria utilize light-driven electrons as an energy source for autotrophic growth

Sangrak Jin, Yale Jeon, Min Soo Jeon, Jongoh Shin, Yoseb Song, Seulgi Kang, Jiyun Bae, Suhyung Cho, Jung Kul Lee, Dong Rip Kim, Byung Kwan Cho

Research output: Contribution to journalArticlepeer-review

Abstract

Acetogenic bacteria use cellular redox energy to convert CO2 to acetate using the Wood-Ljungdahl (WL) pathway. Such redox energy can be derived from electrons generated from H2 as well as from inorganic materials, such as photoresponsive semiconductors. We have developed a nanoparticle-microbe hybrid system in which chemically synthesized cadmium sulfide nanoparticles (CdS-NPs) are displayed on the cell surface of the industrial acetogen Clostridium autoethanogenum. The hybrid system converts CO2 into acetate without the need for additional energy sources, such as H2, and uses only light-induced electrons from CdS-NPs. To elucidate the underlying mechanism by which C. autoethanogenum uses electrons generated from external energy sources to reduce CO2, we performed transcriptional analysis. Our results indicate that genes encoding the metal ion or flavin-binding proteins were highly up-regulated under CdS-driven autotrophic conditions along with the activation of genes associated with the WL pathway and energy conservation system. Furthermore, the addition of these cofactors increased the CO2 fixation rate under light-exposure conditions. Our results demonstrate the potential to improve the efficiency of artificial photosynthesis systems based on acetogenic bacteria integrated with photoresponsive nanoparticles.

Original languageEnglish
Article numbere2020552118
JournalProceedings of the National Academy of Sciences of the United States of America
Volume118
Issue number9
DOIs
StatePublished - 2021 Mar 2

Keywords

  • Acetogenic bacteria
  • Artificial photosynthesis
  • Cadmium sulfide nanoparticle
  • Clostridium autoethanogenum
  • Extracellular electron transfer

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