Membrane processing of liquors from Eucalyptus globulus autohydrolysis

The hemicellulosic fraction of Eucalyptus globulus wood is made up of heteroxylan. E. globulus wood samples were treated with hot, compressed water (hydrothermal or autohydrolysis treatments) to hydrolyse the hemicellulosic fraction. Reaction liquors contained acidic xylooligosaccharides, monosaccharides and non-saccharide products. Autohydrolysis liquors were processed using ultra- and nano-filtration ceramic membranes with cut-offs in the range 1–50 kDa to assess their ability for refining and/or concentrating oligosaccharides. The molecular weight distributions of oligosaccharides in feed, concentrates and permeates were determined, and the effects caused by the several membranes operating in recirculation or concentration modes are discussed on the basis of the compositions of permeates and retentates.