碱处理中温度对不同底物特性木质纤维素结构及酶解的影响

发布时间：2018-10-19 07:55

【摘要】：为研究碱法预处理中温度对不同底物特性的木质纤维素结构及酶解效率的影响,选用柠条锦鸡儿(Caragana korshinskii Kom,简称CKK,以下简称柠条)、水稻秸秆、小麦秸秆为原料,用NaOH溶液分别在常温和高温条件下进行预处理;通过扫描电镜(简称SEM)分析、傅立叶转换红外光谱(简称FTIR)分析、X-射线衍射(简称XRD)分析等分析预处理后木质纤维素的表面形态、化学成分及结晶度的变化,并用纤维素酶对预处理后的木质纤维素原料进行酶解糖化试验。SEM和成分分析结果表明,NaOH溶液碱处理能有效去除木质纤维素的木质素成分,破坏致密的物理结构;FTIR图谱表明,经NaOH溶液处理后,柠条、水稻秸秆和小麦秸秆的木质素结构受到一定程度的破坏,羟基、亚甲基、甲氧基和酯键等部分官能团发生断裂;XRD分析和酶解结果显示,碱处理能破坏木质纤维素原料中的结晶区,增大原料的孔隙率和内表面积,从而增加纤维素酶的可及性和酶解转化率,经过24 h酶解后,高温下碱处理能使水稻秸秆葡聚糖的转化率高达94.87%;其中,温度又作为一个重要的因素影响NaOH溶液碱处理的效果,当温度升高时,NaOH溶液碱处理对木质素的去除效果更好,对底物的物理结构破坏更严重,因此升高温度会促进NaOH溶液碱处理的作用效果。
[Abstract]:In order to study the effect of temperature on lignocellulose structure and enzymatic hydrolysis efficiency of different substrate properties in alkaline pretreatment, Caragana (Caragana korshinskii Kom,), rice straw and wheat straw were used as raw materials. NaOH solution was pretreated at room temperature and high temperature, and analyzed by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to analyze the surface morphology, chemical composition and crystallinity of lignocellulose. The results of SEM and component analysis showed that alkali treatment of NaOH solution could effectively remove lignin from lignocellulose and destroy the dense physical structure. After treated with NaOH solution, lignin structure of Caragana korshinskii, rice straw and wheat straw was destroyed to a certain extent, and some functional groups such as hydroxyl, methylene, methoxy and ester bond were broken, the results of XRD analysis and enzymatic hydrolysis showed that, Alkali treatment can destroy the crystalline region of lignocellulose material, increase the porosity and internal surface area of the raw material, thus increase the accessibility of cellulase and the conversion rate of enzymatic hydrolysis. After 24 h enzymatic hydrolysis, Alkali treatment at high temperature can make the conversion rate of rice straw dextran up to 94.877.Among them, temperature, as an important factor, affects the effect of alkali treatment of NaOH solution. When the temperature increases, the effect of alkali treatment of NaOH solution on the removal of lignin is better. The physical structure of the substrate was destroyed more seriously, so increasing the temperature would promote the effect of alkali treatment in NaOH solution.
【作者单位】：天津科技大学生物工程学院/工业发酵微生物教育部重点实验室;
【基金】：公益性行业(农业)科研专项(编号:201503135-15)
【分类号】：O636.11

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