Study On Production Of Sodium Gluconate By Aspergillus Niger

The thesis was designed to optimize the cultures of producing sodium gluconate by Aspergillus niger and analyze the effects on fermentation in order to produce sodium gluconate effectively.The properties,structure,applications and the fermentation processes of sodium gluconate by Aspergillus niger were introduced in this thesis. A method for the fast determination of sodium gluconate was studied, sodium gluconate reacts with Cu(II)ion to form a stable complex which can be used for its spectrophotometric determination.The optimal culture conditions of Aspergillus niger using shaking-flask were investigated. The efects of temperature, pH, and seed age were studied. The optimal fermentation pH is 6.0 and the seed age temperature are16hours, 30℃.Response surface analysis was applied to optimize the four major factor (pH, temperature, rotate speed, concentration of glucose) for gluconic acid fermentation by Aspergillus niger, the equation was established between those factors and the response. Under optimal conditions, the yield of sodium gluconate obtained 94.7% from 125.2g/L glucose after 24 hours fermentation at 30.7℃, pH=6.0,and the rotation is 267 r/min.