Production of xylooligosaccharides from renewable agricultural lignocellulose biomass

Abstract

Efficient utilization of lignocellulosic biomass requires pretreatment in order to liberate cellulose from lignin and disrupt its recalcitrant crystalline structure before effective enzymatic hydrolysis can take place. Three different pretreatment methods (pressure cooking with dilute alkali and dilute acid as well as alkaline extraction) to recover the xylooligosaccharides fraction from five different grass silage samples, whole crop rye silage and maize silage were compared. The predominant end products released were xylobiose, xylotetraose, xylopentaose and xylohexaose whereas the xylooligosaccharides release pattern differed with the substrate. Maximum values of xylooligosaccharides was found for grass silage 17.26 g/L, whole crop rye silage 3.06 g/L and for maize silage 5.77 g/L. Results reveal the production of high value by-products from agricultural biomass. Advantages of the green-biorefinery concept include a resulting liquid fraction after pretreatment with very low contents of inhibitors such as furfural, hydroxymethylfurfural (HMF) and phenolic compounds.

Keywords:

• xylooligosaccharides
• acidic hydrolysis
• alkaline hydrolysis
• enzyme saccharification
• xylan extraction

Acknowledgements

Enzymes were kindly supplied by Novozymes A/S, Bagsværd, Denmark. We also acknowledge Dan Dhanoa for statistical advice. Part of the work (Leibniz Institute for Agricultural Engineering Potsdam-Bornim) underlying this publication was supported by the European Commission FP 6, Contract No. TREN/06/FP6EN/S07.64183/019884. Rothamsted Research and is supported by Biotechnology and Biological Sciences Research Council (BBSRC), UK. Sreenivas Rao Ravella would like to thank WEFO for financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.