Kinetic modeling of butyric acid effects on butanol fermentation by Clostridium saccharoperbutylacetonicum

A kinetic model of acetone-butanol-ethanol (ABE) fermentation taking into account butyric acid effects was developed and implemented in COPASI. The model was validated by comparing the simulation results with experimental data in batch cultures of Clostridium saccharoperbutylacetonicum under various concentrations of initial glucose (97.1 to 152.6 mM) and butyric acid (90.7 to 153.2 mM). The modeling results suggested that increasing the conversion rates from butyryl-CoA (BCoA) to butanol, from butyrate to BCoA, or from pyruvate to lactate would increase butanol synthesis. Similarly, reducing glucose uptake rate or the reaction rates from pyruvate to acetyl CoA (ACoA), from acetoacetyl CoA (AACoA) to BCoA, or from BCoA to butyrate would improve butanol production. Overall, the kinetic model developed can accurately predict the dynamic behavior of metabolites in ABE fermentation with butyric acid addition, which may subsequently be used to identify genetic manipulation strategies for higher bio-butanol production.