Author(s)

Bo Young Jeon, Il Lae Jung, Doo Hyun Park

Department of Biological Engineering, Seokyeong University, Seoul, South Korea.
Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Daejeon, South Korea.

In this research, metabolic fixation of CO₂ by growing cells of C. acetobutylicum cultivated with electrochemical reducing power was tested on the basis of the metabolites production and genes expression. In cyclic voltammetry, electrochemical oxidation and reduction reaction of neutral red (NR) immobilized in intact cells of C. acetobutylicum was stationarily repeated like the soluble one in the condition without CO₂ but the electrochemical reduction reaction was selectively increased by addition of CO₂. In electrochemical bioreactor, the modified graphite felt cathode with NR (NR-cathode) induced C. acetobutylicum to generate acetate, propionate, and butyrate from CO₂ in defined medium. When H₂ and CO₂ were used as an electron donor and an electron acceptor, respectively, C. acetobutylicum also produced the same metabolites in a defined medium. C. acetobutylicum was not grown in the defined medium without substituted electron donors (H₂ or electrochemical reducing power). C. acetobutylicum cultivated with electrochemical reducing power produced more butyrate than acetate in complex medium but produced more acetate than butyrate in defined medium. The genes of encoding the enzymes catalyzing acetyl-CoA in C. acetobutylicum electrochemically cultivated in defined medium than conventionally cultivated in complex medium. These results are a clue that C. acetobutylicum may metabolically convert CO₂ to metabolites and produce free energy from the electrochemical reducing power.

C. acetobutylicum; CO₂-Assimilation; Electrochemical Reducing Power; Coupling Redox Reaction

B. Young Jeon, I. Lae Jung and D. Hyun Park, "Conversion of Carbon Dioxide to Metabolites by Clostridium acetobutylicum KCTC1037 Cultivated with Electrochemical Reducing Power," Advances in Microbiology, Vol. 2 No. 3, 2012, pp. 332-339. doi: 10.4236/aim.2012.23040.