Recovery and purification of lactic acid from fermentation broth by adsorption

Riedel-de-Haen VI-15, Dowex MWA-1 and Amberlite IRA-35 were employed for lactic acid recovery using model fermentation broth. The broth was first acidified by using a cation exchanger before sorption of lactic acid onto the basic sorbents. Lactic acid was completely recovered from the VI-15 column after 7 bed volumes (BV) of methanol, whereas only 64% was recovered from MWA-1 after 4.5 BV and 18% from IRA-35 after 5 BV. The 5% NH4OH eluted all lactic acid from the MWA-1 column in 1.5 BV with a maximum effluent concentration of 113 mg/mL. The simple recovery scheme employed was not sufficient to produce heat-stable lactic acid. Other broth components were also adsorbed by the basic sorbents and could not be removed during the rinse step, but eluted with lactic acid during the desorption step.