Industrial biogenic residues are a large feedstock for material utilization. Extraction, purification and fractionation of hemicellulose are a challenging task but will lead to a sustainable source of biopolymers for further modification and application in products.

Abstract

Extraction of hemicelluloses from biomass with pressurized hot-water employs the mechanism of autohydrolysis for molecular weight reduction. In a pilot-scale extraction of depectinized apple pomace, molecular weight was 30 kDa with a broad mass distribution including monomers and their degradation products. Ultrafiltration with sequential use of ceramic membranes with decreasing cut-off yielded a suitable fraction with molecular weight of 9 kDa representing 10 % of the extracted hemicelluloses. Further autohydrolytic treatment of the extracted hemicellulose decreases molecular weight while increasing the mass of degradation products. For a series of hydrolysates sequential filtration through ceramic membranes was further tested for fractionation and purification. The efficiency of this fractionation was analyzed by size exclusion chromatography and a total mass balance of the ultrafiltration process is given as an evaluation for suitability of purifying and fraction glycans.