Extraction of Lactic Acid from Aqueous Feeds Using Membrane-Supported Reactive Extraction

Lactic acid extraction and back-extraction were studied using trioctylamine as reactive agent. Different hollow fiber and capillary membrane containing contactors with areas between 0.005 and 1.4 m2as well as various temperatures flow rates and phase ratios of up to 1:40 solvent/feed (S/F) were tested. Despite starting with a low lactic acid concentration of only 0.8 % which allows for most lactic acid-producing bacteria to remain active an aqueous solution with a concentration of 5.8% can be obtained assuming phase ratios of S/F of 1:40 for the extraction and 4:1 for the back-extraction. The technique might be a promising pathway for an alternative downstream processing of lactic acid since it allows the continuous removal of lactic acid from a fermentation broth