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稻草资源丰富,但由于其成分和结构复杂,所含的纤维素、半纤维素难以被酶解成为可发酵性糖。论文采用碱液湿磨法在常温条件下对稻草进行预处理1 h,调查了预处理NaOH浓度对稻草的成分组成和结构、以及酶解中还原糖收率的影响,同时对稻草酶解反应进行动力学分析,求出了米氏方程的米氏常数Km和最大反应速率rmax。实验结果表明,采用1%NaOH溶液对稻草进行预处理后,木质素含量从12.4%降低至10.4%、纤维素结晶结构消失、可及度从639.6%增加至1044.6%。未处理稻草酶解中,还原糖收率为13.4%、Km为66.8 mg/mL、rmax为312.5μmol/(min.mL)。1%NaOH预处理稻草的还原糖收率为41.4%,Km为15.9 mg/mL,rmax为666.7μmol/(min.mL)。木质素去除、纤维素晶体结构消失、可及度改善是稻草酶解反应速率和还原糖收率提高的主要原因。
Straw is rich in resources, but because of its complex composition and structure, contained in the cellulose, hemicellulose is difficult to be enzymatically hydrolyzed into fermentable sugars. In this paper, the lye wet-milling method was used to pretreat straw at room temperature for 1 h. The effects of NaOH pretreatment concentration on the composition and structure of straw and the yield of reducing sugar during enzymolysis were investigated. Kinetic analysis was performed to find the Michaelis constant Km and the maximum reaction rate rmax of the Mie equation. The experimental results showed that the content of lignin decreased from 12.4% to 10.4% with 1% NaOH solution pretreatment, the crystal structure of cellulose disappeared and the accessibility increased from 639.6% to 1044.6%. In untreated rice straw, the reducing sugar yield was 13.4%, Km was 66.8 mg / mL and rmax was 312.5 μmol / (min.mL). The reducing sugar yield of rice straw pretreated with 1% NaOH was 41.4%, Km was 15.9 mg / mL and rmax was 666.7 μmol / (min.mL). Removal of lignin, disappearance of cellulose crystal structure, accessibility is the main reason for the rate of rice enzymatic hydrolysis and reducing sugar yield increased.