Comparison of fumaric acid production by Rhizopus oryzae using different neutralizing agents

摘要

Fumaric acid fermentation in a 10-L bubble column fermenter using different neutralizing agents [CaCO_3, Ca(OH)_2, NaHCO_3] by Rhizopus oryzae ATCC 20344 was examined. It was found that in the fermentation using CaCO_3 as the neutralizing agent the highest fumaric acid weight yield and volumetric productivity were obtained, 53.4% and 1.03 g/L x h~(-1) respectively. In the NaH-CO_3 case, the fumaric acid weight yield and volumetric productivity were 33.7% and 0.69 g/L x h(-1), respectively, much lower than the CaCO_3 case. However, the NaHCO_3 alternative has advantages of cell reuse and simple downstream processing because of the high solubility of sodium fumarate. These advantages may offset the disadvantages of using NaHCO_3 as the neutralizing agent, and the overall fumaric acid weight yield and volumetric productivity will increase.