Method for fermentatively preparing L-amino acids
The invention relates to a method for preparing organic-chemical compounds, characterized in that the following steps are carried out: a) fermentation of a microorganism secreting an L-amino acid, which microorganism contains an overexpressed polynucleotide coding for a polypeptide having polyphosphate-dependent NAD + kinase activity, in a fermentation medium, to form a fermentation broth, b) accumulation of said compound in said fermentation broth and/or in the cells of said microorganism. The invention relates to a method for preparing organic-chemical compounds by fermentation of a microorganism in which a polypeptide having polyphosphate-dependent NAD + kinase is overexpressed.
1. A method for fermentatively producing an L-amino acid product, comprising:
a) fermenting a modified microorganism that secretes L-lysine in a fermentation medium to form a fermentation broth, wherein:
i) compared to an unmodified microorganism or starting strain, said modified microorganism overexpresses a polynucleotide coding for a polypeptide, wherein said polypeptide has polyphosphate-dependent NAD + kinase enzymatic activity and comprises the amino acid sequence of SEQ ID NO:2, SEQ ID NO:4 or SEQ ID NO:6;
ii) compared to an unmodified microorganism, or starting strain, said modified microorganism produces an increased amount of L-lysine;
b) allowing said L-lysine to accumulate in said fermentation broth and/or in the cells of said microorganism;
c) recovering said L-amino acid product from the fermentation broth and/or cells of step b).
2. The method of claim 1 , wherein said polypeptide comprises the amino acid sequence of SEQ ID NO:4 or SEQ ID NO:6.
3. The method of claim 1 , wherein said polypeptide comprises the amino acid sequence of SEQ ID NO:2.
4. The method of claim 3 , wherein said L-amino acid product is a solid product containing at least 10% lysine by weight.
5. The method of claim 3 , wherein said microorganism is a bacterium, yeast or fungus.
6. The method of claim 3 , wherein said microorganism is a bacterium of the genus Corynebacterium or Escherichia.
7. The method of claim 6 , wherein said microorganism is a bacterium of the species Corynebacterium glutamicum or Escherichia coli.
8. The method of claim 7 , wherein said polynucleotide is a recombinant polynucleotide.
9. The method of claim 1 , wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO:1.
10. The method of claim 1 , wherein said polynucleotide comprises the nucleotide sequence of SEQ ID NO:3 or SEQ ID NO:5.
11. The method of claim 1 , wherein, compared to said unmodified microorganism or starting strain, said modified microorganism comprises either:
a) an increased copy number of said polynucleotide, or
b) a stronger promoter controlling transcription of said polynucleotide.
12. The method of claim 11 , wherein said microorganism is a bacterium of the species Corynebacterium glutamicum and said polypeptide consists of the amino acid sequence of SEQ ID NO:2, SEQ ID NO:4 or SEQ ID NO:6.
13. The method of claim 11 , wherein said microorganism is a bacterium of the species Corynebacterium glutamicum and said L-amino acid product is a concentrated aqueous alkaline solution of purified L-lysine or an aqueous acidic biomass-containing concentrate of L-lysine-containing fermentation broth.
14. The method of claim 11 , wherein said microorganism is a bacterium of the species Corynebacterium glutamicum and said L-amino acid product is a solid product containing at least 10% lysine by weight.
15. The method of claim 14 , wherein said solid product comprises either:
a) a pulverulent or crystalline form of purified or pure L-lysine; or
b) L-lysine and biomass.
16. A method for fermentatively producing an L-amino acid product, comprising:
a) fermenting a modified microorganism that secretes L-lysine in a fermentation medium to form a fermentation broth, wherein:
i) compared to an unmodified microorganism or starting strain, said modified microorganism overexpresses a polynucleotide coding for a polypeptide, wherein said polypeptide has polyphosphate-dependent NAD + kinase enzymatic activity and comprises an amino acid sequence that is at least 80% identical to the amino acid sequence of SEQ ID NO:2;
ii) compared to an unmodified microorganism, or starting strain, said modified microorganism produces an increased amount of L-lysine;
b) allowing said L-lysine to accumulate in said fermentation broth and/or in the cells of said microorganism;
c) recovering said L-amino acid product from the fermentation broth and/or cells of step b).
17. The method of claim 16 , wherein said polypeptide comprises an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO:2.
18. The method of claim 17 , wherein said polypeptide comprises an amino acid sequence that is at least 96% identical to the amino acid sequence of SEQ ID NO:2.
19. The method of claim 18 , wherein said polypeptide comprises an amino acid sequence that is at least 98% identical to the amino acid sequence of SEQ ID NO:2.
20. The method of claim 19 , wherein said microorganism is a bacterium of the species Corynebacterium glutamicum and, compared to said unmodified microorganism or starting strain, said modified microorganism comprises either:
a) an increased copy number of said polynucleotide; or
b) a stronger promoter controlling transcription of said polynucleotide.