Lactic acid is produced by chemical synthesis and fermentation. This product and its derivatives are important industrial chemicals in the fields of food processing, pharmaceuticals and cosmetics, and they have attracted great interest as the raw materials of biodegradable polymer，polylactic acid. In the fermentative production of lactic acid, traditionally, the fermentation broth was neutralized with lime and recovered as calcium lactate. After adding sulfuric acid, lactic acid is concentrated by evaporation and purified by methods involving short-path distillation. This recovery and purification of lactic acid from the fermentation broth is the most costly process.
Therefore, many recovery techniques such as diffusion dialysis, solvent extraction, adsorption, chromatographic methods, membrane use, drying and electrodialysis have been proposed. Additionally, the in situ recovery technique during fermentation offers the potential to not only recover lactic acid but also relieve end-product (lactic acid) inhibition. Among the proposed separation techniques, reactive extraction is a promising separation method that can be applied in situ and has the potential to provide a high recovery ratio.