Recovery of Lactic Acid from Corn Stover Hemicellulose-Derived Liquor

Lactic acid is an attractive target platform chemical obtained from biorefinery processes based on renewable resources. This study focuses on the recovery of lactic acid from corn stover hemicellulose-derived liquor. Two processes were investigated comparatively. In process I, under the optimized conditions of 10 wt % trioctylamine/octanol, the extraction efficiency and distribution coefficient of lactic acid were 50.8% and 1.03, respectively. In process II, a salting-out extraction step was introduced, which had significant impacts on the following reactive extraction process. The extraction efficiency and distribution coefficient of lactic acid were about 32.2% and 3.85 times higher than that of process I, respectively. All residual sugars and most of the salts (82.8%) could be removed by the salting-out extraction system used. Additionally, five extraction cycles with back-extraction and solvent regeneration were performed, and the results showed that the extraction system still exhibited stable performance. Effective extraction of lactic acid from crude reaction liquor of corn stover was realized by first salting-out and consecutive reactive extraction, which provided a potential method for recovery of lactic acid from actual biomass-derived liquor.