Reactive liquid-liquid extraction of lactic acid from biobased process streams

Lactic acid is one of the most important biobased bulk chemicals and exhibits a constantly growing market. The main production route of lactic acid is microbial fermentation using carbohydrate materials, where the product inhibition of the produced lactic acid and the high downstream processing costs represent the main drawbacks. In this context, reactive liquid-liquid extraction is regarded as an effective approach to lower the downstream processing costs and to enable in-situ lactic acid isolation. When working with biobased process streams, the high tendency to emulsion or crud formation leads to solvent phase loss and makes the application of conventional extraction equipment more challenging. The goal of this doctoral thesis is to optimize the reactive liquid-liquid extraction of lactic acid from biobased process streams, such as silage extract or fermentation broths.

Besides increasing the efficiency of the process, special attention will be payed to the prevention of unwanted crud formation. This will be accomplished by variation of different process parameters, e.g. process temperature, solvent phase composition or stripping phase composition. Further, the pre-treatment of the respective process stream is addressed.