Process for Preparing High Levels of Interferon Beta

A process for the production of interferon beta in an Escherichia coli host cell comprising:

• a) providing the host cell that is capable of producing the protein;
• and
• b) culturing the cell under conditions effective to induce production of the polypeptide in a medium comprising a complex nitrogen source selected from gelatin digest, casein enzyme hydrolysate, and tryptone, either alone or these media in combination with each other or any of these media in combination with yeast extract, where the process is carried out at a pH at about 6.5 to 7.0 and at a temperature about 37° C.;
• and
• c) the culture media further comprising thiamine at a concentration of at least 3 g/l.