A two steps membrane process for the recovery of succinic acid from fermentation broth

The aim of this study was to investigate the integration of nanofiltration in succinic acid production based on a fermentation. An experimental investigation was carried out with NF 45 membrane and synthetic fermentation broths of increasing complexity containing succinate salt and different impurities like inorganic salts, glucose or other organic acid salts like acetate. The influence of the operating conditions (pH, pressure...) as well as of the broth composition on the NF performances was studied. The mechanisms governing the transfer of the solutes through the membrane were investigated in order to explain the different solute retentions observed according to the fermentation broth composition. Finally, a two-step process including NF in a diafiltration mode followed by reverse osmosis was proposed to perform the purification of succinate from a synthetic fermentation broth containing acetate. It was shown that it is possible to increase the succinate purity from 85% to 99.5% while maintaining the total yield higher than 92%.