Kinetic Characterization and Effect of Immobilized Thermostable β-Glucosidase in Alginate Gel Beads on Sugarcane Juice.

Keerti Keerti,Vinod Kumar,Anuradha Gupta,Ashutosh Dubey,A K Verma

doi:10.1155/2014/178498

Keerti Keerti, Vinod Kumar + Show 3 more

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https://doi.org/10.1155/2014/178498

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Abstract

A thermostable β-glucosidase was effectively immobilized on alginate by the method of gel entrapment. After optimization of immobilized conditions, recovered enzyme activity was 60%. Optimum pH, temperature, kinetic parameters, thermal and pH stability, reusability, and storage stability were investigated. The K m and V max for immobilized β-glucosidase were estimated to be 5.0 mM and 0.64 U/ml, respectively. When comparing, free and immobilized enzyme, change was observed in optimum pH and temperature from 5.0 to 6.0 and 60°C to 80°C, respectively. Immobilized enzyme showed an increase in pH stability over the studied pH range (3.0–10.0) and stability at temperature up to 80°C. The storage stability and reusability of the immobilized β-glucosidase were improved significantly, with 12.09% activity retention at 30°C after being stored for 25 d and 17.85% residual activity after being repeatedly used for 4 times. The effect of both free and immobilized β-glucosidase enzyme on physicochemical properties of sugarcane juice was also analyzed.

Highlights

Introduction βGlucosidase (β-D-glucoside glucohydrolase; EC 3.2.1.21) is a part of multienzyme cellulase complex, whose synthesis and action are intricately controlled by regulatory mechanisms in the organisms that produce these enzymes
Β-Glucosidases hydrolyze β-D-glycosidic bond to release nonreducing β-D-glucose residue and terminal aglycone. These are widely used in the various biotechnological processes including aroma and flavour enrichment [3], discoloration of fruit juices prevention [4], and organoleptic properties of citrus fruit juices improvement, in which the bitterness is in part due to a glucosidic compound, naringin (4,5,7-trihydroxyflavanone-7-rhamnoglucoside) [5]. β-Glucosidase acts as a key enzyme in the enzymatic release of aro-matic compounds from glucosidic precursors present in fruits and fermentation products [6]
The present study describes the immobilization of β-glucosidase in alginate gel beads and the effect of this immobilization on kinetic characteristics of immobilized β-glucosidase in comparison with free enzyme

Summary

Introduction

Introduction βGlucosidase (β-D-glucoside glucohydrolase; EC 3.2.1.21) is a part of multienzyme cellulase complex, whose synthesis and action are intricately controlled by regulatory mechanisms in the organisms that produce these enzymes. Β-Glucosidases hydrolyze β-D-glycosidic bond to release nonreducing β-D-glucose residue and terminal aglycone. These are widely used in the various biotechnological processes including aroma and flavour enrichment [3], discoloration of fruit juices prevention [4], and organoleptic properties of citrus fruit juices improvement, in which the bitterness is in part due to a glucosidic compound, naringin (4,5,7-trihydroxyflavanone-7-rhamnoglucoside) [5]. Β-Glucosidase acts as a key enzyme in the enzymatic release of aro-matic compounds from glucosidic precursors present in fruits and fermentation products [6]. Some of the more significant advantages of immobilized enzymes over their soluble counterparts include the enhanced stability under extreme conditions of temperature, pH, and organic solvents; recovery; and subsequent applicability to continuous processes [9]

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