Abstract:Corn liquefaction liquor was used as raw material，Aspergillus niger was used as fermentation strain，and corn liquefaction liquor fermentation medium was optimized through single-factor screening and orthogonal experiments.By observing the acid-producing and mycelial-ball morphology observations，the optimal media formulation was determined to be：0.7%corn syrup，1.0 g/L （NH4）2SO4，0.1 g/L MgSO4，0.8 mg/L CuSO4，0.02 g/L ZnSO4，2.0 g/L CaCl2，0.1 g/L KCl，0.34 mg/L FeSO4，0.07 g/L inositol.The optimum fermentation conditions were determined on 30 L scale fermenters，the optimum fermentation conditions：18%of initial sugar，the best seed culture age 27 h.The ventilation quantity and speed is controlled and fermentation time was 60 hours.The fermentation results conducted on 30 L scale fermenters showed that the citric acid production was 18.33 g/100 mL and the conversion rate of glucose reached 100.3%.It had higer level with production of citric acid from the corn liquefaction liquor fermentation than corn residue fermentation.