Purification and characterization of inulinase from Aspergillus niger AF10 expressed in Pichia pastoris

The inuA1 gene encoding an exoinulinase from Aspergillus niger AF10 was expressed in Pichia pastoris, and the recombinant enzyme activity was 316 U/ml in a 5 L fermentor, with the inulinase protein accounting for 35% of the total protein of fermentation broth. The hydrolysis rate of mulin can reach 92%, with a 25 U/g inulin enzyme addition, and 90% of fructose content after 6 h. Glucose can significantly inhibit the enzymatic hydrolysis of inulin. This is the first report of glucose inhibition of inulinase-catalyzed hydrolysis. (C) 2004 Elsevier Inc. All rights reserved.