Mutants for the preparation of D-amino acids
AssigneeEvonik Degussa GmbH
InventorsOliver May, Stefan Buchholz, Michael Schwarm, Karlheinz Drauz, Robert J. Turner, Ian Fotheringham
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Abstract
Escherichia. coli mutants which can be used for the synthesis of D-amino acids, and to such a process. The mutants are distinguished by deficiencies in particular enzymes which break down D-amino acids and include those which produce D-amino acids via the carbamoylase/hydantoinase route.
Claims15
An isolated Escherichia coli strain
- having its dadA gene mutated or deleted so that said gene does not express a functional D-amino acid oxidase;
- and
- having its dsdA gene mutated or deleted so that said gene does not express a functional D-serine dehydratase;
- wherein said strain has been transformed with and expresses a D-carbamoylase gene and a D-hydantoinase gene,
- wherein the strain is Escherichia coli strain DSM15182 (ET4), and
- wherein the isolated strain exhibits reduced breakdown of produced D-amino acids when cultured in a suitable medium.
A method for producing a D-amino acid via the carbamoylase/hydantoinase route comprising culturing an isolated microorganism that has been transformed with and expresses a D-carbamoylase gene and a D-hydantoinase gene;
- wherein said microorganism lacks at least one gene that expresses a functional D-amino oxidase and D-amino acid dehydratase;
- wherein said microorganism is selected from the group consisting of Escherichia coli DCM15181 (ET3) and Escherichia coli DSM15182 (ET4), and
- wherein the isolated strain exhibits reduced breakdown of produced D-amino acids when cultured.
An isolated Escherichia coli strain that has been transformed with and expresses a D-carbamoylase gene and a D-hydantoinase gene;
- wherein said strain is Escherichia coli DCM15181 (ET3) that lacks a dadA gene that expresses a functional D-amino oxidase.
Dependencies are inferred from the claim text.