Purification and Properties of an Esterase from Bacillus licheniformis and it’s Application in Synthesis of Octyl Acetate

Esterase plays a major role in the degradation of natural materials, industrial pollutants and also provides an immense contribution to the eco-friendly approaches in various industrial applications.

In the present study, extracellular esterase from bacterial isolate Bacillus licheniformis was purified, characterized and used in the synthesis of octyl acetate.

Purification of esterase from Bacillus licheniformis was achieved using Sephadex G-75 column chromatography. Gas chromatography was used to analyze the octyl acetate synthesis.

The enzyme was salted out using ammonium sulphate precipitation and 60-70% saturation gave maximum specific activity of the enzyme during precipitation. A purification fold of 6.46 and yield of 9.69% was achieved when esterase from Bacillus licheniformis was purified using Sephadex G-75 column chromatography. Native as well as SDS-PAGE analysis gave a single band of 42 kDa. This showed that the enzyme was purified to homogeneity and it was a monomer with molecular weight of 42 kDa. Biochemical characterization of the enzyme revealed that it had optimum temperature of 45°C in 0.1 M Tris-HCl buffer of pH 8.0. On optimizing different parameters, such as molar ratio of reactants, incubation time, temperature, and amount of protein, the % yield of octyl acetate was found to be 77.3%.

In this work, simple method was used to purify esterase and the enzyme was further used in producing esters/products of commercial value within a reasonably short period of 12 h with a maximum yield of 77.3%.