Capability Enhancement of Fumaric Acid Production by Rhizopus arrhizus Through Carbon-Nitrogen Sources Coordination

Abstract

Fumaric acid production from the fermentation process by Rhizopus was considered a potential method. But poor conversion efficiency and low space-time productivity greatly hampered industrial production. Here, we reported improving these problems through carbon-nitrogen sources coordination optimization strategy. Five commonly used nitrogen sources were selected to conduct element analysis and fermentation efficiency comparison. Casein was proven to be the optimum nitrogen source and further investigated in a stirred-tank reactor. It showed that the fermentation cycle was significantly shortened by the application of casein. Combined with optimization of glucose content, the space-time productivity of fumaric acid reached 0.76 g/L h with a yield to 0.31 g/g glucose, which was the highest among the results gotten in the stirred-tank reactor. It illustrated that carbon-nitrogen sources coordination optimization strategy was in favor of the improvement of the fermentation process and laid a promising foundation for the development of fumaric acid industrial production.