【作者】 陈玲；

【导师】 袁兴中； 曾光明；

【作者基本信息】 湖南大学 ， 环境工程， 2009， 硕士

【摘要】 在木质纤维素生产燃料乙醇的研究中,选用更加廉价、易收集处理的原料,提高预处理物料的酶解率和得糖率,是极为有效降低生产成本的途径之一。纤维素酶在生物质转化过程中的重要作用与地位毋庸置疑,设法提高纤维素酶的酶活也是降低生产成本的最重要途径之一。因此,在本次研究课题中,拟选用葵花籽壳为原材料,纤维素酶为研究对象,以磁性Fe₃O₄与游离纤维素酶的生物磁效应机理为指导,探索磁性Fe₃O₄在纤维素酶酶水解中的应用,同时在提高纤维素酶的活力方面进行主要研究,从而达到降低纤维素酶生产成本的目的。本论文的主要研究内容是将磁化后的Fe₃O₄微粒作为一种添加剂,考察其在葵花籽壳的酶解过程中,对纤维素酶的酶活、还原糖浓度、纤维素的转化、水解液的表面张力和pH值的影响和作用。此外,还将以磁性Fe₃O₄微粒作为载体,通过明胶包埋法,吸附固定化纤维素酶,研究磁性固定化酶的酶水解性质,以及添加表面活性剂后对磁性固定化纤维素酶酶活的影响,并初步分析和阐述产生这些变化的原因。研究结果表明,磁性Fe₃O₄添加量为0.5 g/L².0 g/L时,对游离纤维素酶酶活的提高﹑还原糖浓度的增加和纤维素的转化率在48 h后表现出较明显的促进作用。磁性Fe₃O₄添加量为2 g/L时,纤维素酶60 h酶活最高可提高25.9%。添加量为1.5 g/L时,还原糖浓度从6.950 mg/mL提高到8.775 mg/mL;同时,其纤维素的最高转化率达60.531%,明显高于不添加Fe₃O₄样品的纤维素转化率47.932%。此外,分次添加磁性Fe₃O₄的酶活稳定性要优于一次添加。在相同水解条件下,与游离纤维素酶相比,磁性固定化纤维素酶能将还原糖的最高产量从8.775 mg/mL提高到9.162 mg/mL,相比提高4.4%。特别是添加表面活性剂后,还原糖的最高值产量可达9.975 mg/mL,相比提高13.68%。更多还原

【Abstract】 While the technology of transforming lignocellulose into ethanol is studied, choosing low-cost, easily collective and processing raw materials to improve hydrolysate rate and sugar yields, is one of the most effective ways to reduce production costs. In another way, the status of enzymes in the technology of transforming cellulase into ethanol was proved beyond the shadow of a doubt. The technology of improving the cellulase activity also played an important part in the cutting off the production costs. In the paper, refering the sunflower seed hull as the raw materials, the enzymes as the object of study, the magnetic mechanisms of cellulase and cellulase immobilized by Fe₃O₄, the improvement of the cellulase activity were investigated to cut off the cellulase produxtion costs, and to explore the utilization of magnetic Fe₃O₄ particles in the enzymatic hydrolysis.The chief topic of the paper is adding magnetic Fe₃O₄ particles on cellulase in the enzymatic hydrolysis of sunflower seedhull. In the process of enzymatic hydrolysis of sunflower seed hull, the variations of cellulase activity,reducing sugar concentration, cellulose conversion, the analysis of pH and surface tension of hydrolysate were evaluated. In additon, the utilization of magnetic Fe₃O₄ particles as the carrier of cellulase Immobilized by Gelatin adsorption, was used to study the enzymatic hydrolysis quality of cellulase Immobilized by Magnetic Gelatin, to analysis the variations and expatiat on the reasons.The results indicated that after adding magnetic Fe₃O₄, the cellulase activity, reducing sugar concentration and conversion of cellulose had an increased between the 0.5 g/L and 2.0 g/L cases after 48 h. When the additive amount of magnetic Fe₃O₄ was 2 g/L, the cellulase activity at 60 h was improved significantly by 25.9%. It was found that the concentration of reducing sugar was increased from 6.950 mg/mL to 8.775 mg/mL with magnetic Fe₃O₄ 1.5 g/L. Simultaneously,compared with the blank, which the conversion of cellulose was 47.932%, the maximum cellulose conversion of samples with adding magnetic Fe₃O₄ was 60.531%. Besides, the stability of cellulase activity adding in times was better than in one time. It was approved that the cellulase Immobilized by Magnetic Gelatin adsorption had increased the maximum reducing sugar from 8.775 mg/mL to 9.162 mg/mL., which was 4.4% higher compared with the free cellulose under similar hydrolysis conditions.After adding biosurfactant, the maximum reducing sugar was 9.975 mg/mL, which was 13.68% higher than the blank especially.更多还原