Fixation of CO(2) in Clostridium cellulovorans analyzed by (13)C-isotopomer-based target metabolomics

Clostridium cellulovorans has been one of promising microorganisms to use biomass efficiently; however the basic metabolic pathways have not been completely known. We carried out (13)C-isotopomer-based target metabolome analysis, or carbohydrate conversion process analysis, for more profound understanding of metabolic pathways of the bacterium. Our findings that pyruvate + oxaloacetate, fumarate, and malate inside and outside cells exhibited (13)C incorporation suggest that C. cellulovorans exactly fixed CO(2) and partly operated the TCA cycle in a reductive manner. Accompanied with CO(2) fixation, the microorganism was also found to produce and secrete lactate. Overall, our study demonstrates that a part of C. cellulovorans metabolic pathways related to glycolysis and the TCA cycle are involved in CO(2) fixation.