Appeal 2007-1069
Application 10/334,990
STATEMENT OF CASE
Arthrobacter aurescens DSM 3747 is one of the few
isolated microorganisms capable of converting 5-
monosubstituted hydantoins to L-amino acids. The
disadvantage of using A. aurescens cells as [a] biocatalyst is the
low enzyme activity. Especially the L-N-carbamoylase is the
bottleneck for most substrates leading to an increase of the
intermediate L-N-carbamoyl amino acid in the cell, which is not
further converted to the corresponding amino acid.
(Specification 1: 28 to 2: 3.)
The asymmetric bio-conversion to either L- or D- amino acids
involves three enzymes: hydantoinase, hydantoin racemase, and D- or L-
specific carbamoylase (Specification 1: 19-27; 2: 8-16). The claimed
invention is directed to microorganisms (“whole cell catalysts”) transformed
with DNAs coding for hydantoinase, hydantoin racemase, and
carbamoylase, and methods of using the microorganisms to produce
enantiomerically enriched amino acids.
Using whole cell catalysts comprising cloned genes encoding
for a hydantoinase, for a hydantoin racemase and a D- or L-
specific carbamoylase for the conversion of 5-monosubstituted
hydantoins to L- or D-amino acids results in a fast and complete
conversion of racemic mixtures of hydantoins to the
corresponding L- or D-amino acids on industrial scale. This
significantly reduces the production costs due to a reduction of
fermentation and purification costs because all enzymes are
produced in one strain.
(Specification 3: 1-9.)
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