Alleles of the zwf gene from coryneform bacteria

1. An isolated polynucleotide encoding a polypeptide of coryneform bacteria having glucose 6-phosphate dehydrogenase enzyme activity, wherein said polypeptide comprises the amino acid sequence of SEQ ID NO:2, except that any proteinogenic amino acid other than glycine is present at position 321 and/or any proteinogenic amino acid other than serine is present at position 8.

2. The isolated polynucleotide of claim 1 , wherein said isolated polynucleotide comprises the nucleotide sequence of SEQ ID NO:1, except that the codon for the amino acid in position 321 of the protein encoded is for any proteinogenic amino acid other than glycine and/or the codon for the amino acid at position 8 is for any proteinogenic amino acid other than serine.

3. The isolated polynucleotide of claim 1 , wherein, except for the amino acids at positions 321 and 8, said polypeptide consists of the amino acid sequence of SEQ ID NO:2.

4. The isolated polynucleotide of claim 1 , wherein said polypeptide is 514 amino acids in length.

5. The isolated polynucleotide of claim 1 , wherein the amino acid at position 321 of said polypeptide is L-serine.

6. The isolated polynucleotide of claim 1 , wherein the amino acid at position 8 of said polypeptide is L-threonine.

7. The isolated polynucleotide of claim 1 , wherein the amino acid at position 321 of said polypeptide is L-serine and the amino acid at position 8 of said polypeptide is L-threonine.

8. The isolated polynucleotide of claim 1 , wherein said isolated polynucleotide comprises the nucleotide sequence of SEQ ID NO:5, SEQ ID NO:7 or SEQ ID NO:9.

9. The isolated polynucleotide of claim 1 , wherein said isolated polynucleotide comprises the nucleotide sequence of SEQ ID NO:11.

10. A vector comprising the nucleotide sequence of the isolated polynucleotide of claim 1 .

11. An isolated coryneform bacterium comprising a polynucleotide sequence encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2 except that any proteinogenic amino acid other than glycine is present at position 321 and/or any proteinogenic amino acid other than serine is present at position 8, and wherein said polypeptide has glucose 6-phosphate dehydrogenase activity.

12. The isolated coryneform bacterium of claim 11 , wherein said polypeptide comprises an amino acid sequence having a length of 514 amino acids.

13. The isolated coryneform bacterium of claim 12 , wherein said isolated coryneform bacterium is selected from the group consisting of Corynebacterium efficiens, Corynebacterium glutamicum, Corynebacterium thermoaminogenes and Corynebacterium aminogenes.

14. A process for preparing an L-amino acid, comprising:

a) fermenting a coryneform bacterium in a suitable medium, said coryneform bacterium comprising the isolated polynucleotide of claim 1 ;

b) concentrating the L-amino acid in the fermentation broth or in the cells of said bacterium.

15. The process of claim 14 , wherein said polypeptide comprises an amino acid sequence having a length of 514 amino acids.

16. The process of claim 14 , wherein said L-amino acid is purified from the fermentation broth or cells of step b).

17. The process of claim 14 , further comprising:

c) concentrating said L-amino acid in said fermentation broth in step b, collecting said fermentation broth and then removing an amount of from 0 to 100% of the biomass present; and

d) preparing from the composition produced in step c, an essentially dry and shaped product by a method selected from the group consisting of granulation, compacting, spray drying and extrusion.

18. The process of claim 17 , wherein the essentially dry and shaped product obtained in step d) is sprayed with an oil.

19. The process of claim 14 , wherein said L-amino acid is either L-lysine or L-tryptophan.

20. The vector of claim 10 , wherein, except for the amino acids at positions 321 and 8, said polypeptide consists of the amino acid sequence of SEQ ID NO:2.

21. A coryneform bacterium comprising the vector of claim 20 .