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 316U/ml in a 5L fermentor, with the inulinase protein accounting for 35% of the total protein of fermentation broth. The hydrolysis rate of inulin can reach 92%, with a 25U/g inulin enzyme addition, and 90% of fructose content after 6h. Glucose can significantly inhibit the enzymatic hydrolysis of inulin. This is the first report of glucose inhibition of inulinase-catalyzed hydrolysis.