Electrodialysis applied for phenylacetic acid separation from organic impurities: Increasing the recovery

Phenylacetic acid produced biotechnologically is present in phosphate buffer medium containing also organic impurities after production stage. Main aim of this work was to test applicability of electrodialysis for phenylacetic acid separation from organic impurities. Relatively high amounts of phenylacetic acid can be adsorbed on active sites of membranes at the end of electrodialysis process. Electrodialysis of model fermentation broth containing phosphate buffer, phenylacetic add and organic impurities was conducted in two stages. In the first stage, separation of phenylacetic acid from organic impurities occurs and in the second one, phenylacetic acid bound to active sites of the anion-exchange membrane is displaced by an inorganic anion. Both stages of electrodialysis were performed under constant voltage of either 5 V or 10 V. Recoveries reached after the first stage were higher at 10 V with the highest recovery ratio of 60%. The highest reached recovery ratio of phenylacetic acid after the second electrodialysis stage was 95%.