Optimization of Glucose Oxidase Fermentation with Aspergillus niger by Response Surface Methodology

Abstract:

For the purpose of improving the production of glucose oxidase，response surface methodology（RSM） has been employed to optimize the fermentation medium to improve glucose oxidase production by mutational Aspergillus niger. Firstly，a Plackett-Burman design was used to investigate the effects of different factors in the fermentation medium，with three most significant factors being identified as：beef extract peptone，Tw-60 and（NH4）2HPO4. Secondly，the steepest ascent procedure was employed to define the optimal response region for these three factors. Finally，the Box-Behnken method was employed to design the reaction system and the optimal fermentation medium for production of glucose oxidase consisted of the following（g/L）：sugar 87.5，beef extract peptone 3.15，NH4NO3 1.88，（NH4）2HPO4 0.34， KH2PO4 0.25，Tw-60 30.47，corn flour 12.5. Glucose oxidase production after optimization was increasing by a factor of about 93.28% from 45.27 U/mL to 87.5 U/mL. The different adding time of Tw-60 was investigated in 7 L fermentor. The result shows that adding Tw-60 to broth in logarithmic phase can improve glucose oxidase production remarkably，the total glucose oxidase activity reached 92.88 U/mL.