Development, modeling, and simulation of the anaerobic fermentation from glucose to acetic acid by Clostridium thermoaceticum

An obligate anaerobe, Clostridium thermoaceticum, was studied in a simple and efficient controlled environment system. Experiments on both batch fermentation and continuous fermentation have been done to support mathematical modeling and dynamic simulation of the system over a range of operating conditions. Glucose serves as the major carbon source for the final metabolite, acetic acid, in the controlled batch fermentation; however, a small amount of pyruvic acid is found to accumulate during continuous fermentation.;Product inhibition, cell death, and cell maintenance are exhibited in our system. Generally, the fermentation period is about 200 hours. For the batch fermentation the maximum overall cell yield is 0.066 g cell/g glucose and the overall yield of acetic acid is 0.89 g acetic acid/g glucose. For the continuous fermentation the average overall cell yield is 0.058 g cell/g glucose and the average overall yield of acetic acid is 0.88 g acetic acid/g glucose after 100 hours.;The systematic models for batch and continuous fermentation are formulated. Parameters in these models are estimated from batch fermentation and other sources. Simulation by models for the corresponding behavior of batch and continuous cell culture have also been done. A comparison between experiments of continuous fermentation and batch fermentation indicates a distinct advantage of the continuous process.