芦蒿秸秆降解菌株的筛选与鉴定(任务书,论文10000字)
摘要
纤维素在自然界中是一种极其普遍的有机物和能源，它与我们的生活息息相关，但大都还是以特殊状态存在于植物或者土壤中，至今我们还未找到一种绝对简单有效的方法对其充分利用。但根据以往的研究经验，对纤维素的降解能力的高低很大程度上决定了其利用率的高低。于是，越来越多的人开始探究一种更加简单快捷的降解方式。在研究中发现，相对于传统化学法，生物降解法更加优先利用。
本研究以南京八卦洲不同地点泥土、水样、朽木及腐叶为样品，利用纤维素钠为底物，根据菌株在纤维素刚果红培养基上的透明水解圈和菌落直径大小的比值进行初筛，得到4株高产纤维素酶的菌株，分别编号，作为初筛结果。再分别进行复筛，采用摇瓶发酵法，用SBA测酶活，比较得到酶活最高菌株NO3。对产纤维素酶菌株从形态及基因两个方面进行鉴定，验证确定产酶菌株为绿色木酶。接下来对菌株进行酶学性质研究，分别从酶反应的最适温度、酶反应的最适pH值、酶对pH值的稳定性三个方面展开，试验发现酶反应的最适温度为45 ℃，酶反应的最pH值为7 .5。酶对pH 值稳定性的测定结果是产酶在pH值在7 .0～ 7.5范围内, 酶表现较高的稳性, pH值在小于7 .0或者高于7.5时 ,酶活力下降较快。最后，以芦蒿秸秆渣为底物，用绿色木酶来降解，酶活为2.08 U/mL，表明绿色木酶对芦蒿秸秆的降解力较强，有待于工业化大规模应用的进一步开发。
关键词：纤维素酶；筛选；鉴定；酶学性质；
Screening and identification of Artemisia selengensis Straw Degradation Strains
Abstract
Cellulose is one of the most extremely common organic substance and energy sources. In nature, the existence of cellulose substances is very special, which makes it difficult to make rational use of such precious resources. A number of studies have shown that biodegradation is more preferred than other methods in decomposing cellulose. To make cellulose well decomposed into small molecules or some other nutrients, the key problem is to screen and isolate the good strains that can degrade cellulose rapidly.
This study takessoil, water, wood and leafs as amples in different locations of Nanjing Baguazhou, and numbered them, they were screened according to the ratio size of transparent hydrolysis circle and colony diameter in cellulose Congo red medium, then carrying on screening in shake flask fermentation again. the enzyme activity of the strain NO3 was highest. The cellulase producing strain was identified from two aspects of morphology and gene, and the strain was proved to be green wood enzyme. Following this is the study of characterization, experiment showed that the optimum temperature of enzyme reaction is 45℃, the optimum reaction pH value is 7.5. The result showed that the enzyme showed higher stability in the range of pH7.0 to7.5. When the pH value was less than 7.0 or higher than 7.5, the enzyme activity decreased rapidly. Finally, the slag Artemisia selengensis straw as substrate, with green wood to reduce the enzyme, the enzyme activity is 2.08U/mL, showed that Trichoderma enzyme on degradation ability of Artemisia selengensis straw is strong.
Key words: cellulase; screening; identification; enzymatic properties;
目录
摘要 I
Abstract II
第一章文章综述 1
1.1研究背景 1
1.2纤维素概述 1
1.3纤维素酶的概述 1
1.4筛菌的研究进展 1
1.5纤维素酶的应用 2
1.5.1在造纸工业中的应用 3
1.5.2在纺织和干洗业中的应用 3
1.5.3在饲料和食物中的应用 3
1.5.4在医药中的应用 3
1.6本课题的研究意义 4
第二章试验研究 5
2.1 材料与方法 5
2.1.1 样品来源 5
2.1.2 培养基 5
2.1.3试验试剂 5
2.1.4试验仪器 5
2.2 试验方法 6
2.2.1富集 6
2.2.2菌株初筛 6
2.2.3菌株复筛 6
2.2.4菌株鉴定 7
2.2.5 酶学性质的研究 8
2.2.6 酶对芦蒿秸秆的降解 8
第三章结果与讨论 10
3.1 初筛结果 10
3.2 复筛结果 11
3.3 鉴定结果 12
3.3.1形态学特征 12
3.3.2菌种分子鉴定结果 12
3.4 酶学性质的研究结果 14
3.4.1酶反应的最适温度 14
3.4.2 酶反应的最适pH 值 15
3.4.3酶对pH值稳定性的测定结果 15
3.5绿色木酶对芦蒿秸秆的降解结果及初步应用 16
第四章结论与展望 17
4.1结论 17
4.2 展望 17
参考文献 19
致谢 22 |
