Biomass Fractionation after Denaturing Cell Walls by Glycerol Thermal Processing

Denaturing biopolymers allows the transformation of highly organized natural structures into industrially relevant materials such as extruded starch or gelatin. This approach was used to fractionate wood into its biopolymer constituents by treating wood particles in polymer processing equipment at high temperatures in the presence of anhydrous glycerol. Nine severities were studied to assess the impact of time and temperature during processing. After processing, the biomass was stripped of its lignin and xylan by subsequent extractions without addition of added catalysts, leaving a relatively pure cellulose fraction, 84% glucan, as found in chemical pulps. Additionally, 41% of the lignin and 68% of the xylan was recovered in a dry powdered form. The hemicellulose side-chain carbohydrates such as arabinose and galactose were water extracted, while the majority of the mannan remained with the cellulose fiber. High temperature processing for short times in a benign solvent provides significant disruption of the cell wall, while anhydrous glycerol prevents significant degradation of the majority of the biopolymers into oligomers.