Complete Conversion of D,L-5-Monosubstituted Hydantoins with a Low Velocity of Chemical Racemization into D-Amino Acids Using Whole Cells of Recombinant Escherichia coli
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Martínez Rodríguez, Sergio![University of Almería authority University of Almería authority](/themes/Mirage2/images/autoridades/autoridad.png)
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Date
2002Abstract
A reaction system was developed for the production of D-amino acids from D,L-5-
monosubstituted hydantoins with a very slow rate of spontaneous racemization. For
this purpose the D-hydantoinase and D-carbamoylase from Agrobacterium radiobacter
NRRL B11291 were cloned in separate plasmids and expressed in Escherichia coli.
The third enzyme, hydantoin racemase, was cloned from Agrobacterium tumefaciens
C58. The hydantoin racemase amino acid sequence was significantly similar to those
previously described. A reaction system consisting of recombinant Escherichia coli
whole cell biocatalysts containing separately expressed D-hydantoinase, D-carbamoylase,
and hydantoin recemase showed high substrate specificity and was effective toward
both aliphatic and aromatic D,L-5-monosubstituted hydantoins. After optimizing
reaction conditions (pH 8 and 50 °C), 100% conversion of D,L-5-(2-methylthioethyl)-
hydantoin (15 mM) into D-methionine was obtained in 30 min.
Palabra/s clave
D,L-5-Monosubstituted Hydantoins
D-Amino Acids
Conversion
D-hydantoinase
D-carbamoylase
hydantoin racemase
whole cell biocatalysts
Agrobacterium radiobacter
Agrobacterium tumefaciens