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Towards preparative asymmetric synthesis of β-hydroxy-α-amino acids: l-allo-Threonine formation from glycine and acetaldehyde using recombinant GlyA

Paper ID Volume ID Publish Year Pages File Format Full-Text
25194 43559 2007 9 PDF Available
Title
Towards preparative asymmetric synthesis of β-hydroxy-α-amino acids: l-allo-Threonine formation from glycine and acetaldehyde using recombinant GlyA
Abstract

The diastereospecific formation of l-allo-threonine, catalyzed by the serine hydroxymethyltransferase GlyA form Escherichia coli, was studied with regard to the application in continuous processes. Process design will rely on a suitable description of enzyme stability and kinetics under relevant process conditions. Therefore, the effects of addition of organic co-solvents – methanol and acetonitrile – to the reaction mixtures on activity, stability, and diastereoselectivity were investigated. A series of progress curves from batch reactions at 35 °C in 50 mM sodium phosphate buffer pH 6.6 and 50 mM sodium phosphate buffer pH 6.6 in 20% methanol was used to estimate the respective kinetic parameters for an appropriate kinetic model.The experimental data agreed well with a kinetic model for an ordered reaction mechanism of the type bi-uni including the formation of a ternary complex and a pseudo-equilibrium assumption. The model was then applied in order to simulate the performance of the enzyme in an enzyme membrane reactor (EMR) and gave an excellent agreement with the corresponding experimental data. A space time yield of 227 g L−1 d−1 was achieved in a continuous running EMR without significant loss of enzyme activity over 120 h of operation.

Keywords
Aldolase; Enzyme membrane reactor; Enzyme kinetics; Diastereomers; C–C bond formation
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Towards preparative asymmetric synthesis of β-hydroxy-α-amino acids: l-allo-Threonine formation from glycine and acetaldehyde using recombinant GlyA
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 130, Issue 4, 15 July 2007, Pages 402–410
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