摘要：β-葡萄糖苷酶是纤维素酶的组分之一，在纤维素降解过程中可以去除纤维二糖对纤维素酶的抑制从而有效的提高纤维素降解效率，对纤维质乙醇具有重要的意义。本论文通过硫酸二乙酯诱变筛选β-葡萄糖苷酶高产的黑曲霉突变菌株。筛选结果发现：1）以黑曲霉3.316为出发菌种，通过DES诱变得到致死曲线，分析得出最佳的诱变时间是30~40min。2）根据诱变菌株的透明圈直径进行初筛，得到48株菌株。3）发酵培养初筛菌株，根据测定的葡萄糖含量计算菌株的酶活力,发现诱变后的酶活力有所提高。4）计算菌株的比酶活，诱变菌株DES-43的酶活为21±0.34 U/mL，比酶活为11±0.54 U/µg。本实验研究为纤维质乙醇和放大培养提供优良菌株。65507

毕业论文关键词：β-葡萄糖苷酶，黑曲霉，DES诱变

Abstract：β-Glucosidase is one of the components of cellulase, which is important in cellulose -degrading. In this paper, screening of the Aspergillus niger with the high production enzyme of the β-glucosidase by DES mutagenesis was studied. Results were as followed: 1) Aspergillus niger 3.316 was selected as the parent strain, death curve is obtained by DES mutagenesis, and the beast mutagenesis time was 30~40 minutes; 2）obtained 48 mutants by plants screening according diameter of transparent zone; 3）the enzyme activity of the mutants enhanced smaller proportion; 4）activity of the mutant DES-43 was 21±0.34 U/mL, and the relative enzyme activity was 11±0.54 U/µg. This thesis provides excellent strains to cellulose ethanol production.

Keywords: β-Glucosidase, Aspergillus niger, Mutation by diethyl sulfate

目录

1 引言 5

  1.1 β-葡萄糖苷酶在日常生活中的应用 5

  1.2 常规诱变育种技术在选育β-葡萄糖苷酶高产菌株中的研究进展 6

  1.3 β-葡萄糖苷酶的发酵生产概况 6

  1.4 实验思路设计 7

2 材料与方法 8

  2.1 材料 8

    2.1.1 菌株 8

    2.1.2 培养基 8

    2.1.3 主要试剂 8

    2.1.4 仪器设备 8

  2.2 实验方法 9

    2.2.1 PDA培养基的制备 9

    2.2.2 黑曲霉菌株的制备 9

    2.2.3 DES诱变 9

    2.2.4 致死曲线 9

    2.2.5 诱变菌株初筛 10

    2.2.6 诱变菌株复筛 10

    2.2.7 标准葡萄糖苷酶酶活计算 10

    2.2.8 蛋白质测定方法—Bradford法 11

3 结果分析 12

  3.1致死曲线 13

  3.2初筛 13

  3.3复筛 14

    3.3.1 诱变菌株酶活 14

    3.3.2 蛋白含量