木质素降解微生物的分离筛选
时间:2017-05-26 11:23 来源:毕业论文 作者:毕业论文 点击:次
| 摘要：从采集的土样中通过稀释平板和划线分离让其中的菌落生长并获得单菌落，在PDA培养集中加入0.1%愈创木酚制成平板，筛选出12个能产木质素降解酶的菌种，再以木质素为唯一碳源的培养基中选出3株生长最旺盛的优势菌种。对菌株进行初步生理生化鉴定，包括生长曲线、代谢类型、pH对其生长的影响、木质素降解率及木质素降解酶活力。最后以酶活力为指标对菌种的培养条件进行优化，包括氮源的确定、最适pH的确定、最适生长温度及摇床转速的确定，用正交试验来判断各个因素对产木质素降解酶影响程度的大小，找出最佳的条件配置，以获得最高效的酶活力。 结论如下：9274 (1)在28℃下培养8天，木质素降解率为32.42%。 (2)在28℃静置培养8天时，酶活力最大。 (3)静置培养和摇床培养对比试验确定该菌株属于好氧型菌种。 (4)经过单因素试验和优化试验确定了菌株最适氮源为氯化铵，用量为1.0g/L，最适pH为4.5，最适温度为30℃，最适摇床转速为120r/min。 关键词：木质素降解；筛选；鉴定 Separation and screening microbial strains for lignin degradation Abstract：From the sample soil by pour plate and streak plate method to get single colonies, In re-screening, with PDA medium containing 0.1% guaiacol, 12 strains that produce lignin-degrading enzyme were achieved. 3 most vigorous growth and dominant strains were obtained while the isolated lignin was used as the sole carbon in the culture medium. On preliminary physiological and biochemical identification strains, including growth curve, metabolic type, pH influence to the growth of lignin and lignin-degrading enzyme degradation rate vitality. Finally, the enzyme activity as an indicator for the bacteria to optimize the culture conditions, including the determination of nitrogen and pH to determine the optimum temperature and shaking speed determined by orthogonal experiment to determine the various factors on the production of lignin degrading enzymes impact of the size, configuration to identify the best conditions in order to obtain the most efficient enzymes. Conclusions are as follows: (1) Cultured in 28℃for 8 days, the lignin degradation rate was 32.42%. (2) In 28 ℃ static culture for 8 days, the maximum enzyme activity (3) Static culture and shaking culture comparison test to determine the strain belongs to the aerobic bacteria (4) By the test of single factor experiment and optimization to determine the optimum nitrogen source is ammonium chloride, the dosage of 1.0g/L, the optimum pH is 4.5, the optimum temperature is 30 ℃, the optimum rotation speed is 120r/min. Keyword：lignin-degradation; screening; identification 目 录 1. 绪论 1 1.1 木质素的概述 1 1.2 木质素降解微生物 3 1.2.1真菌 3 1.2.2细菌 4 1.2.3放线菌 4 1.3微生物降解木质素的机理 5 1.3.1侧链氧化 5 1.3.2去甲基化和去甲氧基化 5 1.4 本课题目前研究进展 6 1.5.本课题的研究目的和意义 7 2. 实验材料和方法 8 2.1 实验材料 8 2.1.1 土样 8 2.1.2 培养基 8 2.1.3 试剂 8 2.1.5 主要仪器 9 2.2 分析方法 9 2.2.1 降解率的测定 9 2.2.2 木质素降解酶活力的测定 9 2.3 实验方法 10 2.3.1 样品采集 10 2.3.2 菌株分离纯化 10 2.3.3 菌种的初筛 10 (责任编辑：qin) |