Process for the separation and purification of lactic acid from a fermentation medium

A process for the separation and purification of lactic acid from a fermentation medium containing said acid and lactic acid producing microorganisms, wherein said acid is totally or partially in the form of a salt or salts, wherein:

• a) the lactic acid-producing microorganisms are separated from the other components of the fermentation mediums;
• b) the resulting separated medium containing the lactic acid salt(s) is concentrated;
• c) said concentrated separated medium is acidified to a pH below or equal to 3;
• d) the resulting acidified aqueous solution is passed over a cation exchange resin to give a fraction consisting essentially of lactic acid in the free form and at most 25% by weight of lactic acid salt(s), expressed by dry weight relative to the dry weight of said solution;
• e) said fraction is subjected to bipolar fractionating electrodialysis to give an aqueous solution enriched in lactic acid;
• and
• f) the lactic acid is purified, concentrated and recovered from said enriched aqueous solution.