Chromatographic determination of 1, 4-β-xylooligosaccharides of different chain lengths to follow xylan deconstruction in biomass conversion.

Xylooligosaccharides released in hydrothermal pretreatment of lignocellulosic biomass can be purified for high-value products or further hydrolyzed into sugars for fermentation or chemical conversion. In addition, characterization of xylooligosaccharides is vital to understand hemicellulose structure and removal mechanisms in pretreatment of cellulosic biomass. In this study, gel permeation chromatography was applied to fractionate xylooligosaccharides produced from birchwood xylan according to their specific degree of polymerization (DP). Then, each fraction was identified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS); and their concentrations were determined by a downscaled post-hydrolysis method. Based on PAD responses and sugar concentrations for each fraction, a series of response factors were developed that can be used to quantify xylooligosaccharides of DP from 2 to 14 without standards. The resulting approach can profile xylooligosaccharides and help gain new insights into biomass deconstruction.