The invention is directed to a process for the preparation of 2,5-furandicarboxylic acid (FDCA) by fermentation comprising fermenting a suitable starting compound to produce an aqueous solution of a salt of FDCA having a pH of at least 7, optionally removing solids from said solution, e.g. by filtration, subsequently freeze crystallizing the said salt of FDCA from said solution at said pH, isolating the said FDCA salt in the form of solid crystals, preparing an aqueous solution of said salt and crystallizing FDCA as the free acid from said solution at an acidic pH.