Extraction and characterization of native heteroxylans from delignified corn stover and aspen

Abstract

Dimethylsulfoxide-solubilized polysaccharides from delignified corn stover and aspen were characterized. The biomass was delignified by two different techniques; a standard acid chlorite and a pulp and paper QPD technique comprising chelation (Q), peroxide (P), and acid-chlorite (D). Major polysaccharides in all fractions were diversely substituted xylan. Xylan acetylation was intact after chlorite delignification and, as expected, xylan from QPDdelignified fraction was de-acetylated by the alkaline peroxide step. The study of DMSO-extractable xylans from chlorite-delignified biomass revealed major differences in native acetylation patterns between corn stover and aspen xylan. Xylan from cell walls of corn stover contains 2-O-and 3-O-mono-acetylated xylan and [MeGlcA-a-(1 ? 2)][3-OAc]-xylp units. In addition, aspen xylan also contains 2,3-di-O-acetylated xylose. 1,4-b-D-xylp residues substituted with MeGlcA at O-2 position are absent in chlorite-delignified aspen xylan. Sugar composition in accord with NMRspectroscopic data indicated that corn stover xylan is arabinosylated while aspen xylan is not. We have shown that corn stover xylan has similar structure with xylans from other plants of Poales order. No evidence was found to indicate the presence of 1,4-b-D-[MeGlcA-a-(1 ? 2)][Ara-a-(1 ? 3)]-xylp in corn stover xylan fractions.Keywords Biomass Á Biomass delignification Á Plant cell wall Á Glucuronoxylan Á Hardwood xylan Á Corn stover xylan Á Xylan acetylation Á Endoxylanase Á Homo-and-heteronuclear NMR-spectroscopy Á MALDI-TOF MS Abbreviations MGX 4-O-Methylglucuronoxylans GAX Glucuronoarabinoxylans MLG Mixed-linkage glucan MeGlcA 4-O-Methylglucuronic acid QA QPD-delignified DMSO-solubilized HMW fraction from aspen QS QPD-delignified DMSO-solubilized HMW fraction from corn stover CA Chlorite-delignified DMSO-solubilized HMW fraction from aspen CS Chlorite-delignified DMSO-solubilized HMW fraction from corn stover MW Molecular weight DP Degree of polymerization

Effect of Hydrolysis Treatment on Cellulose Nanowhiskers from Oil Palm (Elaeis guineesis) Fronds: Morphology, Chemical, Crystallinity, and Thermal Characteristics

“…The polyethylene bag containing reaction mixture was kept for 1 h at 70 o C. During this process lignin and hemicellulose were dissolved (Naran et al 2009;Banerjee et al 2011;Liu et al 2015), and the resulting pulp slurry was pressed at 15 psi and refined using DD series double disc refiner (Finland Metso corporation) operated at 120 kw power at 5% consistency.…”

Graded Ethanol Fractionation and Structural Characterization of Alkali-Extractable Hemicelluloses from Olea europaea L.

“…Hemicellulose isolation involves the cleavage of the linkages between hemicelluloses and lignin in the lignocellulose matrix and solubilization into extraction solution. Due to the recalcitrant structure of the lignocellulosic material, the raw material is usually subjected to an initial delignification for the preparation of holocellulose before hemicellulose extraction (Cohen 2009;Naran et al 2009;Peng et al 2010a). Currently, alkaline extraction, alkaline peroxide extraction, liquid hot water extraction, and steam explosionbased extraction technologies are widely used to isolate hemicelluloses from lignocelluloses .…”

Alterations of the degree of xylan acetylation inArabidopsisxylan mutants

“…[6][7][8][9][10][11] Recent genetic and molecular analyses of 2 groups of Arabidopsis mutants, rwa and esk1, have provided the first glimpse into the biochemical mechanisms controlling xylan acetylation. [12][13][14] Through analyzing genes that are activated by SND1, a secondary wall master transcriptional switch, 15,16 Lee et al 12 previously demonstrated that simultaneous mutations of 4 Arabidopsis RWA genes result in a reduction in xylan acetylation.…”

“…It further indicates that the relative activities of xylan acetyltransferases and glucuronyltransferases may be one of the factors that contribute to the variations in the degree of xylan acetylation seen in different plant species. [5][6][7][8][9][10][11] We next examined whether the Arabidopsis rwa1/2/3/4 quadruple mutant, which is also defective in xylan acetylation 12 ( Fig. 1; Table 1), had any specific defects in the distribution pattern of acetyl groups on xylan.…”