乙草胺降解菌Sphingomonas sp.DC-6的发酵菌剂制备及应用
毕业论文关键词：发酵；固定化；乙草胺；降解率
Fermentation, preparation and application of acetochlor degrading bacteria Sphingomonas sp. DC-6
Abstract：In this study, Sphingomonas sp. DC-6 was used as the strain, which can effectively degrade acetochlor. First the fermentation medium and conditions was optimized by response surface method, and then it was fed-batch cultured in a 7.5-l bioreactor. Alginate-activated carbon immobilized microspheres (AACM) were mainly prepared through immobilized biosorption of activated carbon and Sphingomonas sp. DC-6 by sodium alginate. The acetochlor-degrading performance of AACM and free strain were studied and compared. Results indicated that the biomass and enzyme production were increased under the optimal fermentation conditions. The biomass and enzyme activity after fermenting 48 h were 1.22 times of those before the optimization of medium. In addition, the optimal preparation conditions of AACM were determined as 10 g/L of alginate, 0.5% of activated carbon, 2% of optimal seed bacteria and 10 g/L of CaCl2. The degradation rate of immobilized microspheres for 30 mg/kg acetochlor solution in 60 h reached 99.54%, which was about 1.49 times higher than that of the free bacterial strain. Besides, after alginate-activated carbon immobilized microspheres were recycled for 3 times, and the ending degradation rate still reached 55.11%. This project will provide a reliable theoretical basis for the industrial production of strain Sphingomonas sp. DC-6 and another application approach for pesticide degradation.
Key words: fermentation；immobilization；acetochlor；degradation rate
目 录
摘要 1
关键词 1
Abstract 1
Key words 1
引言 1
1 材料与方法 2
1．1 材料 2
1．1．1 供试菌株 2
1．1．2 培养基 2
1．1．3 主要试剂与材料 2
1．1．4 主要仪器 2
1．2 方法 2
1．2．1 菌种平板活化 2
1．2．2 种子液及摇瓶培养基的培养 2
1．2．3 发酵条件优化验证 2
1．2．4 发酵罐液态发酵验证 3
1．2．5 制备菌制剂 3
1．2．6 联合固定化 3
1．2．7 固定化微球保存 3
1．2．8 乙草胺水解酶的酶活测定 3
1．2．9 乙草胺含量标准曲线的制作 4
1．2．10 乙草胺降解效果检测 4
1．2．11 乙草胺最大降解量测定 4
2 结果与分析 4
2．1 菌株活化与菌落形态 4
2．2 优化发酵条件摇瓶验证 5