Comparison of in silico and experimentally measured13C-MFA flux ranges for C. acetobutylicum [. A) under wild-type biomass constraint (0.32 mmol gDW−1 h−1, grown in complex media) . B) under reduced biomass constraint (0.07 mmol gDW−1 h−1 , grown in defined media) given that the data were also collected during the transition to the solventogenic phase . Hexokinase (HK) and pyruvate carboxylase (PC) had their experimental values outside the model predicted ranges under the reduced biomass constraint. FVA was performed with a glucose uptake rate of 10 mmol gDW−1 h−1. Full reaction names can be found in the list of abbreviations.