title: Enhancement of fumaric acid production by Rhizopus oryzae using a two-stage dissolved oxygen control strategy.
abstract: Batch fermentative production of fumaric acid by Rhizopus oryzae ME-F12 was investigated in a 7-l stirred tank fermentor under different dissolved oxygen (DO) concentrations. High fumaric acid yield on glucose (0.56 g/g) was achieved under high DO concentration (80%), but the glucose consumption rate and fumaric acid productivity were rather low (0.91 and 0.51 g/l/h). Fumaric acid productivity was enhanced under low DO concentration (30%), but the fuamric acid yield on glucose decreased to 0.52 g/g. In order to achieve the high fumaric acid yield and productivity simultaneously, a two-stage dissolved oxygen control strategy was proposed, in which the DO concentration was controlled at 80% in the first 18 h and then switched to 30%. This was experimentally proven to be successful. Relatively high fumaric acid production (56.2 g/l), high fumaric acid yield on glucose (0.54 g/g), and high glucose consumption rate (1.3 g/l/h) were achieved by applying this strategy. The productivity (0.7 g/l/h) was improved by 37%, 21%, and 9%, respectively, compared with fermentations in which DO concentrations were kept constant at 80%, 60%, and 30%.
authors: College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China.
authors: Yong-Qian
authors: YQ
authors: Fu
authors: Shuang
authors: S
authors: Li
authors: Yao
authors: Y
authors: Chen
authors: Qing
authors: Q
authors: Xu
authors: He
authors: H
authors: Huang
authors: Xiao-Yan
authors: XY
authors: Sheng
mesh_terms: D019149:Bioreactors / Q000382:microbiology; D046508:Culture Techniques / Q000379:methods*; D005285:Fermentation; D005650:Fumarates / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D012233:Rhizopus / Q000378:metabolism*
chemical_list: D005650:Fumarates; C032005:fumaric acid; D005947:Glucose; D010100:Oxygen