Catalytic properties of purified alpha amylase from Aspergillus flavus cultivated on low-cost agricultural substrate

Abstract

Aspergillus flavus isolated from fermented millet flour produced a crude enzyme, which was purified via ammonium sulphate precipitation and subsequent chromatographic techniques. The biochemical characteristics of the purified amylase were thereafter investigated showing activity in a wide range of pH and temperature, with optimal conditions of pH 6.0 and 50 °C. The enzyme retained even 89% of its activity after 1 h at 50 °C and 2 h at pH 6.0. The purified enzyme was stimulated by Ca2+, Zn2+ and Co2+, while Hg2+ and EDTA caused mild inhibition of α-amylase activity. The kinetic indices (Km and Vmax) and molecular weight of the enzyme were estimated in 1.71 mg mL-1, 2.133 μmol min-1 mL-1 and 45 kDa respectively. The catalytic properties of α-amylase from A. flavus makes it a promising candidate for use in various starch processing industries.