Depolymerization of hemicelluloses utilizing hydrothermal and acid catalyzed processes proceed by ultrafiltration as fractionation media

Abstract

Replacement of fossil-based polymers is a current challenge, which needs a broad feedstock of bio-based substitutes produced with a reasonable CO2-footprint. As indigestible biopolymers ß-1,4-hemicelluloses were extracted with an extraction process without usage of chemicals from plant-based industrial residues as a heterogeneous mixture. Requirements for industrial applications as binder in coatings or printing inks the hemicelluloses need to be tailored in size and distribution. Solving these issues hydrothermal (HTD) and acid catalyzed depolymerization (ACD) are used to improve suitability of our hemicelluloses for various applications. Desired degree of polymerization (DP) below 15 could be achieved at 190 °C in 50 min with HTD and at 90 °C in 120 min with 1.5 wt% H2SO4 with ACD, which have been characterized by SEC-MALS-dRI, ATR-IR and elemental analysis. For further improvement of monodispersity and purification ultrafiltration was introduced as fractionation media with 1 and 4 kDa multi-channel ceramic membranes. With this process, hemicelluloses from food processing industry residues will be harnessed as a substitute for fossil-based polymers after tailoring molar mass distribution and chemical modification.

Keywords

• Hydrothermal depolymerization
• Acid catalyzed depolymerization
• Hemicelluloses
• Depectinized apple pomace
• SEC-MALS-dRI
• Depolymerization kinetic