Optimization of fermentation of potato starch by RSM during itanonic acid production

Potato starch was fermented to produce itaconic acid by Aspergillus terreus XL-6, and the optimal fermentation conditions were determined by Response Surface Methodology. Plackett-Burman design was used in the first step to evaluate the effects of six variables on the yield of itaconic acid. Initial pH value, fermentation temperature and rotational speed were screened as significant factors and their levels were further optimized. A second-order polynomial regression model about yield of itaconic acid was set up, and the applicability of the model was verified. A maximum yield of 6.08% was obtained after optimizing conditions of fermentation. The optimum values were initial pH 2.4, temperature 36.7□, rotational speed 197r/min, 7.5% inoculum size, medium volume 60mL/250mL with the duration of fermentation 120h. The results from model validation showed that the prediction value of model had good agreement with the actual measured value and the model was feasible.