BIOREFINERY. Pressurised hot water extraction of acetylated xylan from birch sawdust

Abstract Birch sawdust was extracted using pressurized hot water (PHW), with the ultimate aim of maximizing the yield of large and intact non-cellulosic heteropolysaccharides, i.e. hemicellulose molecules. The extractions were performed using a flow-through vessel. Effects of different extraction temperatures between 140 and 200°C were evaluated. The amount of extracted xylans, as weil as monosaccharides, increased as the temperature rose to 1 90°C, accordingly the degree of polymerization of the xylans decreased. The extracted xylans retained most of the native acetyl groups and were thereby water-soluble after the extraction. The PHW extract contained not only xylan and other hemicellulose-derived oligomers, but fragmented Iignin molecules and some extractives as well. Only trace amounts of furfurals were found in the extract at lower extraction temperatures. An optimal yield of water-soluble, polymeric xylans with the smallest amount of unwanted impurities and degradation products was thus achieved at an extraction temperature of 1 80°C using the flow-through vessel

[1]  A. Heiningen,et al.  Kinetics and mechanism of autohydrolysis of hardwoods. , 2010, Bioresource technology.

[2]  K. Nieminen,et al.  Degradation kinetics of the main carbohydrates in birch wood during hot water extraction in a batch reactor at elevated temperatures. , 2011, Bioresource technology.

[3]  E. Sjöström,et al.  Wood Chemistry: Fundamentals and Applications , 1981 .

[4]  O. Bobleter,et al.  The hydrothermal degradation of cellulosic matter to sugars and their fermentative conversion to protein , 1976 .

[5]  F. Tjerneld,et al.  Characterization of acetylated 4-O-methylglucuronoxylan isolated from aspen employing 1H and 13C NMR spectroscopy. , 2000, Carbohydrate research.

[6]  K. Zeitsch,et al.  The Chemistry and Technology of Furfural and Its Many By-Products , 2000 .

[7]  A. Heiningen,et al.  Characterization and molecular weight distribution of carbohydrates isolated from the autohydrolysis extract of mixed southern hardwoods , 2011 .

[8]  Anna Suurnäkki,et al.  Carbohydrate analysis of plant materials with uronic acid-containing polysaccharides–A comparison between different hydrolysis and subsequent chromatographic analytical techniques , 2009 .

[9]  A. Demirbas,et al.  Biorefineries: Current activities and future developments , 2009 .

[10]  G. Bonn,et al.  Hydrothermolysis — a new process for the utilization of Biomass , 1983, Wood Science and Technology.

[11]  B. Holmbom,et al.  Dissolution and dispersion of spruce wood components into hot water , 1997, Wood Science and Technology.

[12]  A. Ebringerová,et al.  Xylans of industrial and biomedical importance. , 1999, Biotechnology & genetic engineering reviews.

[13]  A. V. van Heiningen,et al.  Hemicellulose Removal from Hardwood Chips in the Pre-Hydrolysis Step of the Kraft-Based Dissolving Pulp Production Process , 2010 .

[14]  G. Bonn,et al.  Hydrothermolysis of Birch Wood as Pretreatment for Enzymatic Saccharification , 1988 .

[15]  H. Sixta,et al.  Autohydrolysis of birch wood , 2011 .

[16]  A. Sundberg,et al.  Chemical characterization of various types of mechanical pulp fines , 2003 .

[17]  H. Ilvesniemi,et al.  Pressurized hot water extraction of Norway spruce hemicelluloses using a flow-through system , 2011, Wood Science and Technology.

[18]  J. Parajó,et al.  Hydrothermal processing of lignocellulosic materials , 1999, Holz als Roh- und Werkstoff.

[19]  O. Bobleter,et al.  Hydrothermal degradation of polymers derived from plants , 1994 .

[20]  C. Wyman,et al.  Impact of fluid velocity on hot water only pretreatment of corn stover in a flowthrough reactor , 2004, Applied biochemistry and biotechnology.