Hydrolysis Of Jerusalem Artichoke By Inulinase Degrading Microorganism

In this dissertation , the optimium conditions for inulinase production and hydrolysis from Aspergillus niger SL-09 were carefully investigated. Flask liquid-state fermentation experiments were carried out. The results showed that the carbon source, nitrogen source, surfactants and the medium pH affected the production of inulinase production significantly. Under the optimum culture condition: 30℃, pH 6.0, 200 r/min, 3 d, the optimum component of the medium for enzyme production was (g/L): inulin 30, corn steep 20, sucrose ester 6, MnSO4·H2O 0.25. The highest inulinase activity reached 45.9 U/mL.The conditions for inulinase characterization were investigated. The following study shown that the optimized catalyze temperatures, substrate concentration and pH were 55℃, 40g/L and pH4.5, respectively.The favorable enzymolysis conditions were 50℃, 10% (v/v) whole liquid culture of Aspergillus niger. When 85.2 g/L total sugar of Jerusalem artichoke was used as the substrate, the highest hydrolytic rate of 99.6% was obtained at 12 h.Succinic acid fermentation from Jersulem artichoke using Aspergillus niger SL-09 and Actinobacillus succinogenes SF-09 was also studied. In the 5 L fermenter with enzymolysis syrup (53.5 g/L) as the substrate, the succinic acid concentration, productivity, and sugar conversion efficiency were 43.8 g/L,,1.22 g/(L·h) and 99.0% at 36 h, respectively.The cells of Aspergillus niger SL-09 were entrapped by barium alginate for inulin hydrolysis and treated by glutaraldehyde after immobilization. The activity yield of the immobilized cells was 49.39%. Various characteristics of immobilized cells were assessed.The optimal pH, temperature, inulin concentration were 4.0, 60℃,20 g/L, respectively. The conversion yield was above 70% throughout the 8 days, meanwhile, the storage stability and the operational stability were greatly improved after immobilization.