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Lactulose production from lactose and fructose by a thermostable β-galactosidase from Sulfolobus solfataricus

Paper ID Volume ID Publish Year Pages File Format Full-Text
18539 42725 2006 6 PDF Available
Title
Lactulose production from lactose and fructose by a thermostable β-galactosidase from Sulfolobus solfataricus
Abstract

The gene encoding a thermostable β-galactosidase from Sulfolobus solfataricus was cloned and expressed in Escherichia coli. We investigated the enzymatic production of lactulose from lactose and fructose by this thermostable β-galactosidase. The optimum pH and temperature for lactulose production by the β-galactosidase were 6.0 and 80 °C, respectively. In thermostability experiments, the enzyme followed first-order kinetics of thermal inactivation, and the half-lives of the enzyme at 75, 80, 85, 90, and 95 °C were 91, 48, 35, 2.6, and 0.72 h, respectively, suggesting that the enzyme is highly stable up to 85 °C. Enzyme activity was increased by the addition of Fe2+ and decreased by Ba2+. The optimum substrate and enzyme concentrations were 40% (w/v) lactose and 20% (w/v) fructose at 3.0 units/ml, respectively. Under the optimum conditions, the β-galactosidase from S. solfataricus produced approximately 50 g/l lactulose in 6 h of reaction time with a productivity of 8.3 g/l h.

Keywords
Lactulose; Thermostable β-galactosidase; Sulfolobus solfataricus; Transgalactosylation
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Lactulose production from lactose and fructose by a thermostable β-galactosidase from Sulfolobus solfataricus
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 39, Issue 4, 2 August 2006, Pages 903–908
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us