COMPARATIVE STUDY OF HEMICELLULOSES OBTAINED BY GRADED ETHANOL PRECIPITATION FROM NANDINA DOMESTICA
The dewaxed cell walls of Nandina domestica were treated by hot water at 75 oC, and obtained the hemicellulosic fraction (Hw). The residues were delignified with NaClO2 and then extracted with 10％ KOH. The five 10％ alkali-soluble hemicellulosic fractions were obtained by neutralization and graded ethanol precipitation. The comprehensive physical and structural characterization of the six hemicellulosic fractions by a combination of sugar analysis, molecular weight determination, FT-IR, thermal analysis, 1H and 13C NMR and HSQC. Larger molecular weight and more linear hemicellulosic fraction H2 (Mw 76690 g/mol, xylose 87.1％) was preferred to precipitate in relatively lower ethanol content of 15％, whereas hemicelllulosic fractions with lower weight and more branches (23940 g/mol, xylose 38.7％) were easily precipitated in higher concentration (80％) ethanol solution. Meanwhile, comparing these hemicelluloses indicated that the smaller Mw was more soluble in the hot water treatment, which mainly comprised glucose (73.4％), and probably resulted from the glucan. In addition, the alkali-soluble hemicelluloses have larger molecular weight and more linear structures, in which xylose is predominant sugar component (38.7％-87.3％). Based on the result of FT-IR and NMR, the alkali-soluble hemicellulosic fraction H3 had a structure composed of the (1→4)-linked β-D-xylopyranosyl backbone with 4-O-methyl-D-glucuronic acid attached to the xylose residues.
hemicelluloses Nandina domestica shrub fractionation
Mao Jianzhen Peng Feng Ma Jianfeng Xu Feng Sun Runcang
Institute of Biomass Chemistry and technology,Beijing Forestry University, Beijing, 10083, China
国际会议
广州
英文
260-264
2010-11-08（万方平台首次上网日期，不代表论文的发表时间）