Method for the production of D-pantothenic acid and/or salts thereof via purification by nanofiltration as adjunct for animal feedstuffs

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

• a) fermenting at least one D-pantothenic-acid-producing bacterium from the Bacillaceae family, the pantothenic acid (pan) and optionally the isoleucine/valine (ilv) biosynthesis of which is deregulated and which forms at least 2 g/l of salts of D-pantothenic acid by fermentation in a culture medium,
• b) salts containing polyvalent cations being fed to the D-pantothenate formed, polyvalent salts of D-pantothenic acid being formed,
• c) the solution containing polyvalent salts of D-pantothenic acid being worked up by nanofiltration, the polyvalent salts of D-pantothenic acid being enriched and
• d) the nanofiltration retentate containing polyvalent salts of D-pantothenic acid being subjected to drying and/or formulation, wherein free β-alanine and/or β-alanine salt is not fed to the culture medium, and wherein deregulated panthothenic acid biosynthesis is achieved by overexpressing one or more genes in the pan and optionally in the ilv synthesis pathways, wherein said overexpressed genes include at least the panD gene.