Structural characterization of xilooligosaccharides from shoots of woody bamboo species

ZELAYA, VÍCTOR MARTÍN; FERNÁNDEZ, PAULA V.; CIANCIA, MARINA

San Martín

Simposio; 3º Simposio Argentino de Glicobiología; 2019

CONICET - UNSAM - FIL

Bamboo is one of the mostly fast growing natural resources, andit has great potential to be used as a valuable feedstock forbiorefinery. Bamboo shoots are the new culms that arise from therhizomes, containing nodes and internodes in a verticallyminiaturized form. Young shoots of Phyllostachys aurea andGuadua chacoensis (Poales) showed glucuronoarabinoxylans(GAX) as the major hemicellulosic components, being extractedin important quantities with 1M KOH (12.1% and 10.3% of the cellwall material, ratio Xyl:Ara:GlcA, 100:67:8 and 100:28:8,respectively). Their structure was determined by methylationanalyses and NMR spectroscopy. The degree of ramification ofboth xylans was very different, so they were consideredappropriate substrate models for enzymatic treatment.GAX was treated with Driselase ® (a mixture of endo- and exoenzymes) to generate xylo-oligosaccharides (XOS). Yields ofdigestion were ∼80% and the oligosaccharides were fractionatedby size-exclusion chromatography on Biogel P-2 using water aseluant. Analysis of the oligosaccharides showed mixtures ofxylans with different DP and the presence of a β-(1→3)-glucan,so efforts were done to eliminate this contaminant beforedigestion.Elucidation and understanding of the pure xilooligosaccharidesfrom bamboo play an important role in the efficient conversion ofbamboo into bioproducts.