Simultaneous Fermentation and separation using
Pervaporation Technique of Acetone-Butanol-Ethanol Fermentation: A Mathematical Approach

Abstract

Inhibition due to accumulation of products at higher concentration or toxic levels is considered one of the major problems in the simultaneous fermentation of acetone-ethanol and butanol.Butanol inhibits the process after a certain level of concentration. Various techniques are
available for separation of butanol but pervaporation is most sought after as it is more effective and efficient. Biochemistry of ABE fermentation helps us understand the overall mechanism and pH dependency of the process. Here we consider the overall process of fermentation and
pervaporative separation represented in form of simple mathematical model to explain its intricacies. The set of differential equation were solved using Berkeley Madonna 8.0 version differential equation solver. The inhibition constant for the process was determined and rp factor
for including pervaporation effect into the model was taken into account. It was found inhibition constant has an important role in the overall process and also rp factor had pronounced effect on the concentration of products and substrate in the process. Minor modification in rp factor lead to large variation in the fermentation dynamics. After several trial runs it was concluded rp factor is dependent on the type of membrane considered for pervaporation. Apart from this the biomass concentration in both models reached similar level a fact supporting both the models.