稻草秸秆的碱性臭氧预处理效果

Effects of alkaline ozone pretreatment on rice straw

为了研究碱性臭氧预处理对稻草秸秆酶水解、表观结构及成分的影响,将稻草秸秆碱性臭氧预处理后进行酶水解,对处理前后的稻草秸秆进行了扫描电镜观察及成分分析,并对处理后溶液进行了紫外光谱分析。结果表明:碱性臭氧预处理能将稻草秸秆中的木质素氧化降解为小分子的有机酸,降低了稻草秸秆中木质素的含量,提高了纤维素的含量。扫描电镜观察显示经碱性臭氧预处理过的稻草秸秆,机械组织暴露,孔隙度大,酶解的有效比表面积大。在pH值5.0、每单位底物加酶量31.2mg/g、45℃条件下,碱性臭氧预处理稻草秸秆酶水解120h时还原糖达到了902mg/g,糖化率为92.57%。在相同酶解条件下,碱性预处理与未处理稻草秸秆的糖化率分别为74.90%与53.53%。碱性臭氧预处理稻草秸秆的糖化率明显高于碱性预处理与未处理稻草秸秆的糖化率。

To study the effects of alkaline ozone pretreatment on enzymatic hydrolysis,composition and the surface morphology of rice straw,alkaline ozone pretreatment and enzymatic hydrolysis of rice straw,and the scanning electron microscopic analysis and the component analysis of untreated and treated rice straw were performed,The solutions from the pretreatment were examined by UV/VIS-spectrophotometer.The results showed that lignin of rice straw was oxidative degradated to small molecular organic acid by alkaline ozone pretreatment.Alkaline ozone pretreatment dropped the content of lignin and increased the content of cellulose of rice straw.The scanning electron microscopic analysis showed that mechanical tissue of rice straw was fully emerged and the porosity was increased.Thus,the effective specific surface area available to enzymatic hydrolysis of rice straw increased.The maximum yield of reducing sugars from rice straw was 902 mg/g by alkaline ozone pretreatment and enzymatic saccharification（45℃,pH 5.0,120 h） using 31.2 mg/g enzyme,and the ratio of enzymatic saccharification was 92.57%.The enzymatic saccharification ratios of the alkaline pretreated and untreated rice straw were 74.90% and 53.53%,respectively,at the same enzymatic saccharification condition.The enzymatic saccharification ratio of the alkaline ozone pretreated rice straw was higher evidently than the alkaline pretreated and untreated rice straw.