Fractional study of alkali-soluble hemicelluloses obtained by graded ethanol precipitation from sugar cane bagasse.

摘要: The two hemicellulosic fractions were subsequentially extracted with 5% and 8% NaOH aqueous solution at a solid to liquid ratio of 1:25 (g mL(-1)) 50 degrees C for 3 h from the water, 1 3% NaOH-treated sugar cane bagasse, subfractionated into six preparations by graded ethanol precipitation method concentrations 15%, 30% 60% (v/v). Sugar composition molecular weight analysis showed that, an increasing concentration ethanol, subfractions both higher Ara/Xyl ratios weights obtained. In other words, 15% 60%, increased 0.043 in H(1) 0.088 H(3) 0.040 H(4) H(6), weight-average 42 430 (H(1)) 85 510 (H(3)) g mol(-1) 46 130 (H(4)) 64 070 (H(6)) mol(-1), respectively. results obtained Fourier transform infrared, composition, (1)H (13)C nuclear magnetic spectroscopy that alkali-soluble hemicelluloses had backbone xylose residues beta-(1-->4)-linkage branched mainly through arabinofuranosyl units C-2 and/or C-3 main chain, whereas differences may occur distribution branches along xylan backbone.