Cell culture media

1 . A culture medium comprising at least one N-lactoyl-amino acid and/or salts thereof, wherein the culture medium is a chemically defined medium and is a dry powder medium, wherein the N-lactoyl-amino acid is selected from N-lactoyl-leucine, N-lactoyl-isoleucine, N-lactoyl-valine, N-lactoyl-phenylalanine, N-lactoyl-tyrosine and/or N-lactoyl-methionine.

2 . The culture medium according to claim 1 , characterized in that the cell culture medium comprises one or more of the components of formula I:

with R 1 + being H + or Na + , K + , Mg 2+ , Ca 2+ , Li +

and R 2 being the characteristic residue of the amino acid.

3 . The culture medium according to claim 1 , characterized in that the cell culture medium comprises the sodium salt of the one or more N-lactoyl amino acids.

4 . The culture medium according to claim 1 , characterized in that the cell culture medium comprises the one or more N-lactoyl amino acids and the corresponding amino acids and/or salts thereof.

5 . The culture medium according to claim 2 , characterized in that the medium comprises the one or more N-lactoyl amino acids and/or salts thereof but not the corresponding amino acids and/or salts thereof.

6 . A method for producing a cell culture medium according to claim 1 by

a) mixing one or more N-lactoyl-amino acids according to formula I with other components of the cell culture medium; and

b) subjecting the mixture of step a) to milling.

7 . A process for culturing prokaryotic or eukaryotic cells by

a) providing a bioreactor, and providing a cell culture medium according to claim 2 and dissolving said cell culture medium in water or an aqueous buffer;

b) mixing the cells to be cultured with the cell culture medium; and

c) incubating the mixture of step b).

8 . The process according to claim 7 , characterized in that the bioreactor is a perfusion bioreactor.

9 . A process for culturing prokaryotic or eukaryotic cells in a bioreactor by

(a) filling the cells into the bioreactor;

(b) incubating the cells in the bioreactor; and

(c) adding a medium to the bioreactor, continuously over the whole time or once or several times within the cells incubation time;

whereby the medium is prepared by providing a cell culture medium according to claim 1 and dissolving said cell culture medium in water or an aqueous buffer.

10 . The process according to claim 9 , characterized in that the N-lactoyl amino acid is N-lactoyl leucine and/or N-lactoyl isoleucine and/or salts thereof.