Abstract Using the strain of Rhizopus oryzae ME-F12, the fermentation conditions for fumaric acid were studied for the purpose of optimizing both fumaric acid production and productivity. An orthogonal experiment was designed to investigate the influence of glucose concentration, urea concentration, seed age and inoculation size. The optimal seed age and inoculation size was determined as 36h and 6ml, respectively. A Desirability function based on response surface analysis was further applied to perform the multiple variable optimization. The best glucose and urea concentration were determined as 132.73g/l and 0.0586g/l, respectively. The predicted value for fumaric acid production, productivity and the Desirability value were 71.42g/l, 0.804g/(l.h) and 0.966, respectively. Verification experiment was carried out on a 5L fermentor. After a 88h fermentation period, 130g/l glucose was converted into 66.5g/l fumaric acid with the productivity of 0.755 g/(l.h). Comparing to the value before optimization, the production and productivity of fumaric acid were increased by 13.9% and 15.8%. Results indicated that both the production and productivity were successfully optimized simultaneously, which laid a solid foundation for the further scale-up.
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