Method for producing an amino acid using a bacterium overexpressing an rhtC gene

Patent metadata

Field	Value
Publication number	US-9394346-B2
Application number	US-10645505-A
Country	US
Kind code	B2
Filing date	Apr 15, 2005
Priority date	Dec 23, 1998
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

The present invention describes a bacterium which has an ability to produce an amino acid and in which the rhtC gene encoding a protein having an enhanced activity of imparting L-threonine resistance to a bacterium expressing the protein. Preferably, the bacterium further includes an rhtB gene encoding for a protein having an enhanced activity of imparting to a bacterium L-homoserine resistance expressing the protein. The present invention also describes a method of cultivating the bacterium in a culture medium to produce and accumulate amino acids in the medium, and the amino acid is recovered from the medium.

First claim

What is claimed is:

1. A method of producing an L-amino acid selected from the group consisting of L-homoserine and L-threonine comprising the steps of:
A) cultivating in a culture medium an Escherichia coli which has been modified to increase expression of a DNA, wherein expression of said DNA is increased by increasing the copy number of said DNA or replacing a promoter sequence of said DNA with a promoter sequence which functions in said Escherichia coli , wherein said DNA comprises the nucleotide sequence of nucleotides 187 to 804 of SEQ ID NO: 3;
B) removing solids including cells from the medium; and
C) purifying said L-amino acid from the medium obtained in step B).

2. A method of producing a branched chain L-amino acid comprising the steps of:
A) cultivating in a culture medium an Escherichia coli which has been modified to increase expression of a first DNA comprising the nucleotide sequence of nucleotides 187 to 804 of SEQ ID NO: 3,
and a second DNA comprising the nucleotide sequence of nucleotides 557 to 1171 of SEQ ID NO: 1,
wherein said expression is increased by increasing the copy number of said first and second DNAs or replacing a promoter sequence of said first and second DNAs with a promoter sequence which functions in said Escherichia coli;
B) removing solids including cells from the medium, and
C) purifying said branched chain L-amino acid from the medium obtained in step B).

3. The method according to claim 2 , wherein said branched chain L-amino acid is L-valine or L-leucine.

4. A method of producing an L-amino acid selected from the group consisting of L-homoserine and L-threonine comprising the steps of:
A) cultivating in a culture medium an Escherichia coli which has been modified to increase expression of a DNA, wherein expression of said DNA is increased by increasing the copy number of said DNA or replacing a promoter sequence of said DNA with a promoter sequence which functions in said Escherichia coli , wherein said DNA comprises a nucleotide sequence that encodes a protein comprising the amino acid sequence of SEQ ID NO:4;
B) removing solids including cells from the medium; and
C) purifying said L-amino acid from the medium obtained in step B).

5. A method of producing a branched chain L-amino acid comprising the steps of:
A) cultivating in a culture medium an Escherichia coli which has been modified to increase expression of a first DNA that comprises a nucleotide sequence encoding a protein comprising the amino acid sequence of SEQ ID NO: 4,
and a second DNA that comprises a nucleotide sequence encoding a protein comprising the amino acid sequence of SEQ ID NO: 2,
wherein said expression is increased by increasing the copy number of said first and second DNAs or replacing a promoter sequence of said first and second DNAs with a promoter sequence which functions in said Escherichia coli;
B) removing solids including cells from the medium, and
C) purifying said branched chain L-amino acid from the medium obtained in step B).

6. The method according to claim 5 , wherein said branched chain L-amino acid is L-valine or L-leucine.

Assignees

• Livshits Vitaliy Arkadyevich
• Zakataeva Natalia Pavlovna
• Aleshin Vladimir Veniaminovich
• Belareva Alla Valentinovna
• Tokhmakova Irina Lyvovna
• Ajinomoto Kk

Inventors

• Livshits Vitaliy Arkadyevich
• Zakataeva Natalia Pavlovna
• Aleshin Vladimir Veniaminovich
• Belareva Alla Valentinovna
• Tokhmakova Irina Lyvovna

Classifications

• C12P13/08 Primary

  Lysine; Diaminopimelic acid; Threonine; Valine · CPC title

• C07K14/245 Primary

  Escherichia (G) · CPC title

• C12P13/06

  Alanine; Leucine; Isoleucine; Serine; Homoserine · CPC title

• C12N1/20 Primary

  Bacteria; Culture media therefor · CPC title