The Effect of Sodium Hydroxide Treatment of Rice Straw on In situ Disappearance of Hemicellulose and Lignin in its Cell Wall
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In situ disappearance of cell wall constituents of the untreated and NaOH-treated rice straw was examined in detail. In situ cellulose digestion of rice straw was significantly improved by treatment with 4% NaOH. Hemicellulose in the cell walls of rice straw abundantly contained galactose and xylose, followed by arabinose, glucose, and uronic acids. In situ digestion of xylose residues in hemicellulose of the straw was inferior to that of other monosaccharides, but that of the straw was remarkably improved by the NaOH-treatment. The same amount of guaiacyl- and syringyl- lignins was released from the untreated rice straw during in situ digestion. On the other hand, more abundant syringyl-lignin than guaiacyl-lignin was released from NaOH-treated rice straw during the in situ digestion. In situ disappearance of ester-linked p-coumaric and ferulic acids from the untreated rice straw was larger than that of the ether-linked acids. While, in situ disappearance of ether-linked p-coumaric and ferulic acids from the NaOH-treated rice straw was larger than that of the ester-linked acids. The results obtained in this study suggest that the partial destruction of a network structure built up from hemicellulosic polysaccharides and lignin in rice straw cell walls by NaOH-treatment makes it easy for the access of cellulolytic microorganisms and their cellulases to cellulose and accelerates the in situ cellulose digestion of rice straw.
- Nihon Chikusan Gakkaiho
Nihon Chikusan Gakkaiho 72(1), 19-25, 2001-01-01
Japanese Society of Animal Science