Study on the fermentation medium optimization based on cellulose as raw material to produce citric acid by Aspergillus niger SY0607

An optimal process about citric acid deep submerged fermentation with Aspergillus niger XSY0607 was gained as follows: the optimal culture medium was consisted with rice straw, peptone, NH4NO3 and beef extract as carbon source, organic, inorganic nitrogen source and growth factor, respectively. Plackett- Burman design was applied for final culture medium of citric acid deep submerged fermentation, and the ratio of the recipe, which was consisted by rice straw, peptone, NH4NO3, beef extract, KH2PO4, KH2PO4 and Fe SO4·7H2O, was 6%, 4.5%, 0.5%, 0.75%, 0.15%, 0.045% and 0.0015%, respectively. Range analysis showed the influence of the components to the citric acid fermentation.As a result, the effect for the fermentation, from strong to weak was rice straw, peptone, NH4NO3, KH2PO4, Mg SO4, Fe SO4·7H2O and beef extract. Medium was optimized using citric acid fermentation tests conducted, citric acid production was 83.6mg / m L, increasing 31.83% compared with level before optimization.