Journal
BIOCHEMICAL ENGINEERING JOURNAL
Volume 58-59, Issue -, Pages 33-38Publisher
ELSEVIER
DOI: 10.1016/j.bej.2011.08.011
Keywords
Immobilized enzymes; beta-galactosidase; Alginate; Glucose; Kinetic parameters; Lactose
Funding
- Federal University of Uberlandia
- FAPEMIG
Ask authors/readers for more resources
The objective of this work was to compare the properties of free and immobilized beta-galactosiclase (Aspergillus oryzae), entrapped in alginate-gelatin beads and cross-linked with glutaraldehyde. The free and immobilized forms of the enzyme showed no decrease in enzyme activity when incubated in buffer solutions in pH ranges of 4.5-7.0. The kinetics of lactose hydrolysis by the free and immobilized enzymes were studied at maximum substrate concentrations of 90 g/L and 140 g/L, respectively, a temperature of 35 degrees C and a pH of 4.5. The Michaelis-Menten model with competitive inhibition by galactose fit the experimental results for both forms. The K-m and V-m values of the free enzyme were 52.13 +/- 2.8 mM and 2.56 +/- 0.3 g(glucose)/L min mg(enzyme), respectively, and were 60.30 +/- 3.3 mM and 1032.07 +/- 51.6 g(lactose)/min m(catalyst)(3), respectively, for the immobilized form. The maximum enzymatic activity of the soluble form of eta-galactosidase was obtained at pH 4.5 and 55 degrees C. Alternatively, the immobilized form was most active at pH 5.0 at 60 degrees C. The free and immobilized enzymes presented activation energies of 6.90 +/- 0.5 kcal/mol and 7.7 +/- 0.7 kcal/mol, respectively, which suggested that the immobilized enzyme possessed a lower resistance to substrate transfer. (C) 2011 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available