γ射线辐照降解木聚糖的机理研究  

Study on the Degradation Mechanism of Xylan by Gamma Rays Irradiation

作　　者：武小芬[1] 陈亮[1] 陈静萍[2] 苏小军[3] 齐慧[1] 王克勤[1] 邓明[1] 

机构地区：[1]湖南省农业科学院湖南省核农学与航天育种研究所/湖南省农业生物辐照工程技术研究中心,湖南长沙410125 [2]湖南省农业科学院湖南省农业生物技术研究中心,湖南长沙410125 [3]湖南农业大学湖南省种质创新与资源利用重点实验室,湖南长沙410128

出　　处：《核农学报》2017年第5期889-898,共10页Journal of Nuclear Agricultural Sciences

基　　金：公益性行业(农业)科研专项(201503135-12)

摘　　要：为了探讨γ射线辐照降解半纤维素的机理,以木聚糖为模型化合物,经0、200、400、600、800、1 000、1 200 k Gy剂量的辐照后,采用扫描电镜(SEM)、傅里叶拉曼光谱(FT-Raman)、气相色谱质谱联用仪(GC-MS)研究其表观形貌结构、分子结构及降解产物的变化特征。结果表明,γ射线辐照处理后木聚糖表观形貌结构发生破坏,多孔性增加;随着辐照剂量升高,木聚糖3 354 cm^(-1)处拉曼光谱峰强度降低且峰位发生红移,1 122 cm^(-1)和1 093 cm^(-1)处拉曼光谱峰强度逐渐减弱,表明木聚糖分子中的氢键、糖苷键发生破坏;木聚糖降解产物的GC-MS分析表明,辐照处理后木聚糖乙酸乙酯提取液中共检测到18种脂肪酸类化合物、5种糖类化合物和2种呋喃类化合物,其相对含量分别在1 200、800和1 200 k Gy达到最大值(16.59%、1.46%和1.03%)。本研究结果为木聚糖γ射线辐照降解产物全利用提供了支持。To understand the mechanism of hemicellulose degradation by irradiation, xylan was used as a model compound in this study. The characteristic difference of apparent topography, molecular structure and degradation products of xylan after γ-ray irradiation with different doses of 0, 200, 400, 600, 800, 1 000, 1 200 kGy were analyzed by Scanning Electron Microscopy（SEM）, Fourier Transform Raman Spectroscopy（FT-Raman）, and Gas Chromatography Mass Spectrometry（GC-MS）. The results showed that the apparent topography in xylan was damaged and also increase in porosity of xylan. The intensity of Raman Spectra of 3 354 cm^-1 decreased with the location of peak showing a red shift, and the intensity of Raman Spectra of 1 122 cm^-1 and 1 093 cm^-1 decreased with the increasing dose of γ irradiation, which illuminated the hydrogen bonds and glycosidic bonds of xylan being fractured, respectively. Analyzed degradation products from ethyl acetate extract of xylan after irradiation by GC-MS showed 18 kinds of fatty acid compounds, 5 kinds of saccharides and 2 kinds of furan compounds, and the relative contents of these three compounds group reached the maximum level of 16.59%, 1.46% and 1.03%, at the irradiation dose of 1 200 kGy, 800 kGy and 1 200 kGy, respectively. This study provides support on degradation mechanism of lignocellulose and comprehensive utilization of xylan after γ-irradiation pretreatment.

关 键 词：Γ射线辐照 木聚糖 结构 降解产物 降解机理 

分 类 号：O636.1[理学—高分子化学]