Functionalized agarose as an effective and novel matrix for immobilizing Cicer arietinum β-galactosidase and its application in lactose hydrolysis

Abstract

The present study demonstrates the immobilization of β-galactosidase from Cicer arietinum on a simple and inexpensive matrix, glutaraldehyde functionalized agarose (GFA), to suggest its potential application in hydrolyzing whey lactose in biotechnology industries. The designed matrix provided large surface area for the immobilization of β-galactosidase, apart from exhibiting greater biocatalytic activity in terms of selectivity, loading and stability. GFA retained 83% enzyme activity as a result of immobilization. Soluble and GFA bound Cicer arietinum β-galactosidase showed the same pH and temperature-optima at pH 5.0 and at 50 °C, respectively. However, immobilized enzyme exhibited a greater fraction of activity at both acidic and basic pH, and at higher temperature ranges. GFA bound enzyme lost only 20 % enzyme in the presence of 3% galactose, and retained 70 % activity even after its sixth repeated use. Immobilized enzyme showed pronounced lactose hydrolysis from whey in batch processes at 55 °C as compared to enzyme in solution.

Keywords
agarose; β-galactosidase; Cicer arietinum; glutaraldehyde; whey hydrolysis