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.