NaOH-Fenton试剂预处理桑木的纤维素酶分段酶水解研究

采用分段酶水解木质纤维原料的方法，以NaOH-Fenton试剂预处理桑木为原料，通过在反应过程中及时移除葡萄糖和纤维二糖，减轻产物的抑制作用，最终达到提高酶水解得率和缩短酶解反应时间的目的。实验结果表明：纤维素酶用量为15FPIU/g（以纤维素计，下同）时，在三段（8+8+8h）水解过程中，经第一段水解，纤维素酶反应速率从1.25g/（L·h）提高到2.21g/（L·h），第二段水解后，酶反应速率为1.54g/（L·h），比未分段水解的酶反应速率提高了73%；当纤维素酶用量为40FPIU/g时，三段（8+8+8h）水解得率增至88.08%；三段（8+8+8h）水解充分利用了酶解残渣上的结合酶进行后续水解。对纤维素酶在预处理桑木上的吸附情况进行研究，发现桑木经NaOH-Fenton试剂预处理后，对纤维素酶的最大吸附量为8.08mg/g，预处理增加了纤维素酶与桑木间的吸附位点。

Process Resrarch of Multi-stage Enzymatic Hydrolysis of NaOH-Fenton Pretreated Mulberry Wood

During the multi-stage enzymatic hydrolysis of lignocellulosic materials, the product inhibitions were reduced by the removal of end products at each stage to enhance the hydrolysis efficiency and shorten the hydrolysis time with NaOH-Fenton pretreated mulberry as raw material. During the three-stage (8+8+8h) hydrolysis, as the enzymatic dosage was 15FPIU/g(calculated by the mass of cellulose, similarly here in after), enzymatic average reaction rate increased from 1.25 to 2.21g/(L·h) at the first stage, and after the second stage, it reached 1.54g/(L·h) and increased rapidly by 73% comparing with that of unsegmented hydrolysis.When enzymatic dosage was 40FPIU/g, the three-stage (8+8+8h) hydrolysis could reach 88.08%.Multi-stage hydrolysis made full use of the absorbed cellulase on substrate.The classical Langmuir adsorption isotherm was used to fit the cellulase enzyme adsorption on substrates.The adsorption capacity of cellulase on NaOH-Fenton pretreated mulberry was studied with the maximum adsorption capacity of 8.08mg/g substrate.The adsorbed sites were enhanced in the pretreatment process.