Immobilization of Aspergillus oryzae β galactosidase on concanavalin A-layered calcium alginate-cellulose beads and its application in lactose hydrolysis in continuous spiral bed reactors

Shakeel Ansari,Qayyum Husain

doi:10.2478/v10026-011-0043-4

Abstract

Immobilization of Aspergillus oryzae β galactosidase on concanavalin A-layered calcium alginate-cellulose beads and its application in lactose hydrolysis in continuous spiral bed reactors In this study, Aspergillus oryzae β galactosidase was immobilized on concanavalin A layered calcium alginate-cellulose beads as a bioaffinity support. Immobilized enzyme showed a remarkable broadening in temperature-activity profiles as compared to the native enzyme and exhibited 65% activity in the presence of 5% galactose. Michaelis constant (Km) was 2.57 mM and 5.38 mM for the free and the immobilized β galactosidase, respectively. Crosslinked β galactosidase showed greater catalytic activity in the presence of Mg2+ and was more stable during storage at 4°C for 6 weeks. Immobilized enzyme hydrolyzed 67% lactose in milk in 8 h and 85% lactose in whey in 9 h in the stirred batch process at 50°C. The continuous hydrolysis of lactose by crosslinked β galactosidase in spiral bed reactor exhibited 93% and 88% hydrolysis of lactose at flow rate of 20 ml/h and 30 ml/h, after 1 month operation, respectively.

Highlights

Β Galactosidase (3.2.1.23) is a hydrolytic enzyme that catalyzes the breakdown of lactose into glucose and galactose
Immobilized β galactosidase was used in a stirred batch process for the hydrolysis of lactose from milk and whey at various temperatures and in a spiral bed reactor for continuous hydrolysis of lactose in solution
We developed a hybrid gel of calcium alginate-cellulose beads which were layered with Concanavalin A (Con A). galactosidase from Aspergillus oryzae was immobilized on Con A layered support

Summary

INTRODUCTION

Β Galactosidase (3.2.1.23) is a hydrolytic enzyme that catalyzes the breakdown of lactose into glucose and galactose It is found in plants, animals and microorganisms. The widespread industrial application of enzymes is often hampered by their lack of long term operational stability and shelf-storage life, their cumbersome recovery and re-use. These drawbacks can generally be overcome by immobilization of enzymes, and a major challenge in industrial biocatalysis is the development of stable, robust and preferably insoluble biocatalysts[4,5]. Immobilized biocatalyst can be reused several times and provides several benefits, especially in the food technologies, including easy separation from reaction mixture, no contamination of the product by the enzyme, operational and long term stability, continuous processing and multienzyme reaction systems[6]. Immobilized β galactosidase was used in a stirred batch process for the hydrolysis of lactose from milk and whey at various temperatures and in a spiral bed reactor for continuous hydrolysis of lactose in solution

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION