Modeling the synthetic gas fermentation for bioethanol production

Abstract

The productivity of bioethanol from the synthetic gas anaerobic fermentation by Clostridium jungdahlii is still very low when compared to other bioethanol fermentation methods. The low mass transfer rate of CO, CO2, and H2 gases to the liquid fermentation broth has been considered a major bottleneck in the overall process. Another possible bottleneck is the low concentration of biomass as the real catalyst for bioethanol production. A repeated batch fermentation configuration is proposed to solve the biomass concentration problem. This paper presents the evaluation of the repeated batch configuration for syngas anaerobic fermentation. A model for syngas fermentation has been developed and was used to simulate the effects of repeated batch configurations on bioethanol productivity. The results indicated more than a 50% increase in bioethanol productivity can be achieved by running this fermentation configuration.