Enzymatic Processing of Rice Husk Autohydrolysis Products for Obtaining Low Molecular Weight Oligosaccharides

Abstract

Rice husks were enzymatically treated in aqueous media to cause the hydrolytic degradation of xylan. The reaction liquors (raw or refined by nanofiltration and ion exchange) were treated with endoxylanases to reduce the degree of polymerisation (DP) of the reaction products. Operating at the optimal temperature and pH of each enzyme, the effects of enzyme loading and reaction time were assessed. The enzyme Shearzyme 2x led to the highest proportion of oligomers with DP in the range 2–3, whereas the other endoxylanases (Pentopan Mono BG and Pulpzyme HC) gave mainly oligomers with DP in the range 4–5 or 6–7.

Key Words:

• Autohydrolysis
• rice husks
• substituted xylooligomers
• xylooligosaccharides
• xylanases

ACKNOWLEDGEMENTS

The authors are grateful to the Spanish Ministry of Science of Technology for the financial support of this work (in the framework of the Research Project “Development of technologies for the integral benefit of industrial byproducts,” reference CTQ2005-00745/PPQ, which had partial financial support from the FEDER funds of the European Union).