Purification of lipase from Aspergillus fumigatus using Octyl Sepharose column chromatography and its characterization.

Abstract

Lipases are ubiquitous biological macromolecules which have many industrial and environmental applications. The purpose of this study was to purify lipase from Aspergillus fumigatus by using Octyl Sepharose column chromatography. The enzyme was purified by ammonium sulfate precipitation and hydrophobic interaction chromatography which resulted in sevenfold purification. The molecular weight of protein using Native-PAGE was found to be 70 kDa. The apparent molecular weight by SDS-PAGE was found to be 35 kDa which indicated that the enzyme was homodimer. The optimum temperature and pH for activity of the enzyme was found to be 40 °C and 9.0, respectively. The kinetic parameters Vmax and Km of the purified lipase were 10.42 µmol min-1 mg-1 and 9.89 mM, respectively. Detergents Tween-20 and Triton X-100 inhibited enzyme activity. However, there was minimal loss of enzyme activity with SDS and Tween-80. All metal ions inhibited the enzyme activity. Among solvents, maximum loss (65%) in the enzyme activity was in hexane.