Integrated System of Fed Batch ABE Biosynthesis and Solvent Recovery by Pervaporation

Anaerobic fermentation of glucose substrate by Clostridium acetobutylicum bacteria at 34-39 °C produces butanol, acetone, and ethanol solvents as metabolites. In the case of batch and fed batch bioreactors, the control of butanol concentration in the fermentation broth is recommended for diminishing its inhibitory effect on the bacterial system. Solvent recovery from batch or fed batch bioreactors by using an ultrafiltrationpervaporation system could be an efficient solution to improve the process performances. A mathematical model was developed in order to describe the dynamics of solvent production in an integrated system of fed batch fermentation and solvent recovery. Simulations performed under various operating conditions were used for optimizing the biosynthesis process, i.e., for maximizing the solvent production and minimizing the substrate concentration in the fermentation medium. Initial substrate concentration in the bioreactor, feed flow rate, feed substrate concentration, starting time of feed and ultrafiltration-pervaporation, surface area of ultrafiltration and pervaporation units were selected as process control variables.