Method for producing D-pantothenic acid and/or salts thereof via purification by electrodialysis as an additive for animal feed

1. A process for preparing D-pantothenic acid and/or salts thereof which comprises

a) culturing at least one bacterium from the Bacillaceae family which produces D-pantothenic acid and in which the biosynthesis of pantothenic acid (pan) and/or isoleucine/valine (ilv) is deregulated and which forms at least 2 g/L of salts of D-pantothenic acid by fermentation in a culture medium,

b) passing the D-pantothenate-containing fermentation solution through at least one ion-selective membrane by applying an electric field, wherein the concentration of monovalent ions selected from the group consisting of ammonium, potassium, sodium and chloride, and/or polyvalent ions selected from the group consisting of iron, phosphate and/or sulfate ions is reduced in the D-pantothenate-containing solution,

c) adding a calcium base and/or magnesium base to the resulting solution containing free D-pantothenic acid to set the pH to between 3-10, a solution being obtained which contains calcium and/or magnesium pantothenate and

d) subjecting the calcium pantothenate- and/or magnesium pantothenate-containing solution to drying and/or formulation wherein no free β-alanine and/or β-alanine salt is fed to the culture medium.

2. A process as claimed in claim 1 , wherein the bacterium is of the genus Bacillus.

3. A process as claimed in claim 1 , wherein, in step a) a content of D-pantothenic acid and/or salts thereof of at least 10 g/l of culture medium is formed.

4. A process as claimed in claim 1 , wherein, in step c), the pH of the solution is set to 5-10.

5. A process as claimed in claim 1 , wherein, in step c), the pH of the solution is set to 5-9.

6. A process as claimed in claim 1 , wherein, in step b), monopolar and/or bipolar ion-exchange membranes are used.

7. A process as claimed in claim 1 , wherein, in step b), monopolar ion-exchange membranes are used.

8. A process as claimed in claim 1 , wherein, in step b), monoselective ion-exchange membranes are used.

9. A process as claimed in claim 1 , wherein the pH of the D-pantothenic-acid-containing fermentation solution, before the treatment in step b), is set to the isoelectric pH of D-pantothenic acid.

10. A process as claimed in claim 1 , wherein, in step b), monopolar and/or bipolar ion-exchange membranes are used and current densities of 1-100 mA/cm 2 are set for the monopolar ion-exchange membranes.

11. A process as claimed in claim 1 , wherein, in step b), monopolar and/or bipolar ion-exchange membranes are used and current densities of 1-150 mA/cm 2 are set for the bipolar ion-exchange membranes.

12. A process as claimed in claim 1 , wherein, in step b), the concentration of monovalent cations is reduced to a concentration of ≦1 g/kg of solution.

13. A process as claimed in claim 1 , wherein, for neutralization, calcium hydroxide, calcium carbonate, calcium oxide, magnesium hydroxide and/or basic magnesium carbonate is added in the form of a solid and/or as aqueous suspension to the solution in step c).

14. A process as claimed in claim 1 , wherein an aqueous suspension comprising 2-55% by weight of calcium hydroxide is added to the solution in step c).

15. A process as claimed in claim 1 , wherein an aqueous suspension comprising 2-65% by weight of calcium carbonate is added to the solution in step c).

16. A process as claimed in claim 1 , wherein an aqueous suspension comprising 2-60% by weight of magnesium hydroxide is added to the solution in step c).

17. A process as claimed in claim 1 , wherein an aqueous suspension comprising 2-25% by weight of basic magnesium carbonate is added to the solution in step c).

18. A process as claimed in claim 1 , wherein, in step c) a suspension is obtained which contains calcium pantothenate and/or magnesium pantothenate.

19. A process as claimed in claim 1 , wherein the bacterium is genetically modified such that cells of the bacterium contain β-alanine in increased concentrations compared with a corresponding non-genetically modified bacterium.

20. A process as claimed in claim 1 , wherein, in step a) a content of D-pantothenic acid and/or salts thereof of at least 40 g/l of culture medium is formed.