Application of Solubility Parameter Theory to Organosolv Extraction of Lignin from Enzymatically Hydrolyzed Cornstalks

Abstract

The Hildebrand solubility parameter (delta-value) was applied to explain the effect of organic solvent concentration on lignin removal during organosolv extraction of lignin from enzymatically hydrolyzed cornstalks under atmospheric pressure and low temperature (≤ 75 °C) without additional catalyst. The -value of lignin, calculated using the group-contribution method, was 13.70 (cal/cm3)1/2. The proximity of the delta-value between organic solvent-water and lignin explained the delignification capacity of the organic solvent-water. The concentration of organic solvent in the aqueous mixture that led to the highest delignification (i.e., 34.5%, 41.8%, and 53.7% delignification for ethanol-water, 1,4-dioxane-water, and tetrahydrofuran-water, respectively) was around 65 to 75% vol., which was in keeping with the prediction by the solubility parameter theory.

Keywords

• Organosolv extraction
• Biorefining
• Solubility parameter
• Enzymatically hydrolyzed cornstalk