巨菌草的木素及半纤维素分析

Studies on Lignin and Hemicellulose of Pennisetum Sinese Grasses

关键词:  巨菌草  超微结构  木素分布  半纤维素

Key Words:Pennisetum sinese grasses  ultrastructure  lignin distribution  hemicellulose

摘要:通过碱性硝基苯氧化法测定巨菌草原料中木素结构单元的比例,采用透射电子显微镜(TEM)研究了巨菌草纤维的超微结构和木素分布情况；采用红外光谱研究了巨菌草原料中木素的结构,并与常规的硫酸盐浆和烧碱-蒽醌浆中残余木素结构进行了对比；使用离子色谱法分析了巨菌草原料半纤维素的组成。结果显示,巨菌草原料中愈创木酚基木素结构单元含量较高,达75.63%,对羟苯基木素结构单元和紫丁香基木素结构单元含量较少,分别为10.52%和13.85%。通过TEM观察巨菌草纤维超微切片,巨菌草纤维次生壁外层（S1）较薄；纤维细胞次生壁中层（S2）较厚,占据了细胞壁厚度的大部分,约为S1层的4倍左右,占细胞壁的80%以上；而次生壁内层（S3）最薄。离子色谱分析结果表明,木糖是巨菌草原料半纤维素中最主要的单糖,其含量为56.84%,其次为葡萄糖,其含量为42.48%,阿拉伯糖极少,仅为0.66%；未检测到甘露糖和半乳糖,说明巨菌草原料半纤维素中含痕量或不含甘露糖和半乳糖。

Abstract:In this study, the lignin structure units of Pennisetum sinese grasses were analyzed by HPLC. Results indicated that the content of G-lignin in the raw material was higher, at 75.63%, the contents H-lignin and S-lignin were less, at 10.52% and 13.85% respectivly. The ultrastructure of the grass’s fibers was studied by TEM, the observation confirmed that the S1 layer of the fiber’s cell wall was thin, S2 layer was thick. The thickness of S2 layer was about four times of S1 layer, accounted for more than 80% of the cell wall. The S3 layer was the thinnest. The infrared spectrum of the lignin in raw material, lignin in the kraft pulp and lignin in NaOH-AQ pulp were analyzed. The change of lignin structure in the processes of kraft pulping and NaOH-AQ pulping was studied. The monosaccharide composition of Pennisetum sinese grasses’ hemicellulose was analyzed by ion chromatography (IC). The results showed that xylose was the main monosaccharides with the content of 56.84%, the content of glucose was 42.48%, and arabinose 0.66%. Mannose and galactose were undetected, indicating the raw materials did not contain the mannose and galactose or only contained trace content.