Production, purification and characterization of tannase from Aspergillus tamarii

Abstract

The production of tannases by Aspergillus tamarii was evaluated in submerged cultures using tannic acid and gallic acid as substrates. Two tannases, designated as TAH I and TAH II were produced in gallic acid submerged cultures. TAH I, responsible for 70% of the total tannase activity was purified to apparent electrophoretic homogeneity with 18.35% yield. The enzyme is a homodimeric protein with molecular mass of 180 kDa and 40.5% of its weight corresponds to carbohydrates. TAH I exhibited optimal activity at 30°C and pH 5.5 and was stable over a large pH range (3.0 to 9.0) and at temperatures up to 40°C. With methyl gallate as substrate, the enzyme presented a K_M of 0.77 mM and a V_max of 682.8 U/mg proteins. The enzyme was inhibited by metal ions but showed relative resistance to organic solvents and surfactants. Since the enzyme is active over a wide range of pH and temperature, it is potentially useful in food and pharmaceutical industries.

Key words: Aspergillus tamarii, enzyme purification, submerged culture, tannase.