Production, purification and physicochemical properties of an Exo polygalacturonase from aspergillus Niger SW06

Abstract

In this study, exo-polygalacturonase (exo-PG) production from Aspergillus Niger SW06 was optimized by central composition design and high amount of 21.51 units mL-1 could be achieved in optimizing growth conditions. Both gel filtration and ion exchange chromatography revealed a single exo-PG activity peak, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified protein showed a single band with a molecular mass of 66.2 kDa. The purified enzyme exhibited maximal activity in the presence of 1% citrus pectin at the temperature of 55 °C and pH of 5.0. The enzyme was stable within the pH range of 3.0-5.0 and below 60 °C. The Michaelis constant (Km) and maximum velocity (Vmax) of the enzyme was found to be 0.58 mg mL-1 and 20.66 μmol (mL min)-1, respectively. The thermostable and acidic nature for the activity of this exo-PG make it possible to have wide range of industrial applications.