Kinetic study of substrate dependency for higher butanol production in acetone–butanol–ethanol fermentation

A kinetic simulation model of acetone–butanol–ethanol (ABE) fermentation of xylose (ModelXYL) was proposed by substituting Embden–Meyerhof–Parnas (EMP) pathway equations in the glucose model (ModelGLC) by pentose phosphate (PP) pathway equations of xylose utilization. We estimated the equation parameters of the PP pathway and set other equation parameters to the same as those in ModelGLC, by which ModelXYL exhibited an r2 value of 0.901 between the experimental time course of metabolites with initial xylose concentrations ranging from 40.7 to 292 mM and the calculated values. The results with the developed model suggested that Clostridium saccharoperbutylacetonicum N1-4 has a robust metabolic network in acid- and solvent-producing pathways. Furthermore, sensitivity analysis revealed that slow substrate utilization would be effective for higher butanol production; this coincided with the experimental results. Therefore, we consider the proposed model to be one of the best kinetic simulation candidates describing the dynamic metabolite behavior in ABE production.