^60Co γ辐照对稻草纤维组织及酶解效果的影响

EFFECT OF ^(60)Co γ-RAYS IRRADIATION ON RICE STRAW FIBRE STRUCTURE AND ENZYME HYDROLYZATION

用60Coγ射线处理干稻草秸秆及粗纤维,评价辐照对稻草纤维组织降解作用以及提高稻草秸秆纤维酶降解效果。采用DNS法和硫酸-苯酚法分别测定稻草辐照样品热水浸提液中水溶性还原糖和总糖的含量,通过高效气相色谱分析稻草秸秆各辐照处理提取液中还原糖各组分的变化,并用电子显微镜扫描观测辐照对稻草秸秆纤维组织结构的影响。结果表明,用1000~1500kGy的剂量处理稻草秸秆,能有效破坏稻草的纤维组织结构,特别是稻草表面硅晶结构和纤维结构,且随辐照剂量加大破坏程度增强,辐照稻草热水浸提液水溶性还原糖和总糖含量显著增加。辐照与酶复合处理后稻草秸秆纤维的转化率提高到88.7%,辐照稻草秸秆酶降解后的水溶性还原糖含量达到214.4mg/g,总糖含量达758.5mg/g,极显著地提高甘露糖、半乳糖、葡萄糖、阿拉伯糖、木糖含量,其中葡萄糖含量提高最大,占单糖总量的62.64%,其次是甘露糖。辐照对稻草秸秆木质素降解无明显影响。

The effect of improving enzyme hydrolyze of rice straw was estimated with treating dry rice straw and raw fiber by ^60Co γ-rays irradiation. The water-soluble deoxidize carbohydrate and total carbohydrate of ^60Co γ-rays irradiated rice straw and raw fibres were measured by DNS method and vitrol-phenol method. The changes of deoxidize carbohydrate groups of irradiated hydrolyzing rice straw were analyzed by gas chromatography. The organism structures of irradiated rice straw were scanned by electron microscope, the results showed that 1000- 1500kGy ^60Co γ-irradiation doses effectively destroyed rice straw＇s organism structures, especially the silicon crystal structures, and along with irradiation doses increased the breakage degree enlarged significantly. The contents of the water-soluble deoxidize carbohydrate and total carbohydrate of rice straw increased significantly. Treated by both irradiation and enzyme, the cellulose transform rate of rice straw was 88.7 %, which is better than that only treated by ^60Co γ-irradiation or enzyme. The content of water-solubility deoxidize carbohydrate of the treated rice straw was 214.4mg/g and the total carbohydrate of straw was 758.5mg/g. The contents of mannose, galactose, glucose, arabinose and xylose increased significantly, among those carbohydrate, the glucose＇s increment was the largest and account for 62.64 %, and mannose＇ s increments was the second. The contents of lignin of the rice straw were not influenced obviously by irradiation treatment.