Biochemical characterization of an exo-polygalacturonase of strain Aspergillus terreus PA3A5T and its application in fruit juice clarification

This study aimed to characterize an exo-PG from Aspergillus terreus PA3A5T and evaluate its application in the clarification of fruit juices. Exo-PG was obtained by submerged fermentation and it was purified by ion-exchange chromatography and gel filtration. The enzyme presented molecular mass of 95.2 kDa, with maximum activity at 70 °C in a pH of 4.0 and remaining stable in an acid pH at 60°C. FeCl2, SnCl2, CoCl2, ZnSO4, NaCl, Al2(SO4)3, MgCl2, MnCl2, and CuSO4 ions activated the enzymatic activity, and PbCl2 inhibited it completely. The value of Km was 1.83 mg mL-1 and Vmax was 335 U mg-1. The A. terreus PA3A5T exo-PG proved to be very effective in the clarification process of the juices, significantly reducing viscosity and color.