【作者】 江虹；

【导师】 尹华；

【作者基本信息】 暨南大学 ， 环境科学， 2010， 硕士

【摘要】 PBDEs构成的污染及其所带来的生态风险已引起了人们的极大关注。本研究以广东省汕头市贵屿镇电子废弃物集散及拆卸地环境中的十溴联苯醚(BDE209)为研究对象,对苏云金芽孢杆菌对BDE209的降解性能及其影响因子进行了研究,主要包括：BDD209好氧降解菌的筛选、鉴定及降解性能；在有生物表面活性剂存在的情况下,微生物对BDE209的降解特性；所筛菌株在BDE209-Cd复合污染体系中,对BDE209的降解特性以及对Cd的吸附特性；BDE209的好氧降解机理。从污染土壤中分离得到1株对Cd有较强的耐受性的BDE209高效降解菌J-1,经鉴定为苏云金芽孢杆菌。菌株的投菌量、菌龄、培养液pH值、温度、污染物浓度、通氧量、底物浓度、盐度对BDE209降解有较大影响。蔗糖作为外加碳源能够最大程度地促进BDE209的降解。生物表面活性剂的加入对J-1降解BDE209有较大的促进作用。污染物初始浓度,表面活性剂浓度、培养温度、pH、溶解氧等能对生物表面活性剂促进J-1对BDE209的降解产生较大的影响。提前1d加入生物表面活性剂能更大限度的促进J-1对BDE209的降解。在BDE209-Cd复合污染体系中,菌龄为12-24h之间的J-1对BDE209以及Cd的修复效果最佳。J-1对BDE209的降解动力学方程基本符合一级动力学。J-1的投加方式对其联合修复BDE209-Cd复合污染有较大的影响。10-20mg／1的表面活性剂能促进J-1对BDE209-Cd复合污染的联合修复。从对J-1的细胞结构电镜扫描图来看,J-1能在BDE209-Cd复合污染体系中保持完整的细胞结构,表明其对该种复合污染有较强的耐受性。酶促降解研究表明,菌株J-1的胞内／外酶均对BDE209有降解作用,胞内酶的作用更为明显。pH、温度、通氧量等环境因素会影响胞外酶的降解活性；Cd在一定浓度范围内能促进酶促降解。FT-IR、GC-MS分析表明,在微生物的作用下,BDE209的结构发生了变化,在其对BDE209的降解过程中,有羟基、羧基等含氧基团的产生,同时脱去其苯环上的Br,生成八溴联苯醚。更多还原

【Abstract】 People have been great concerning on PBDEs pollution and its correspondingly ecological risks existed in E-waste recycling area. The research performed on the characteristic and impact factors of BDE209 degradation by Bacillus thuringiensis. In the work, a strain being able to degrade BDE209 in aerobic condition was screened, identified and its characteristic degrading BDE209 was investigated. The effect of bio-surfactant, Cd on BDE209 degradation by the strain was also observed. Furthermore, the mechanism of BDE209 degradation by the strain was explored in the aerobic condition.The strain, isolated from the contaminated soil, strongly tolerable of Cd and effective in degrading BDE209 was identified as Bacillus thuringiensis and named as Bacillus thuringiensis J-1. The factors such as inoculation amount, cell age, pH, temperature, pollutant concentration, dissolved oxygen, substrate concentration and salinity significantly affect the efficiency of BDE209 degradation by J-1. Sucrose as the additional carbon source could mostly promote J-1 degrading BDE209.Biosurfactant could enhance the efficiency of BDE209 degradation by J-1. The factors, for example initial concentration, surfactant concentration, temperature, pH, dissolved oxygen etc., could greatly impact on BDE209 degradation by J-1 in the presence of bio-surfactant. Treating the BDE209 solution forl day with the bio-surfactant could effectively increased the efficiency of BDE209 degradation by J-1.In BDE209-Cd combined pollution system, the J-1 whose age was 12-24h degraded BDE209 and absorbed Cd effectively. The dynamic equation of BDE209 degradation by J-1 met the first order kinetics. The way of bacteria inoculation had significant influence on the remediation of BDE209-Cd combined pollution. Addition of 10-20mg/l of bio-surfactants could improve the removal efficiencies of BDE209 and Cd in combined pollution. The result of electron microscope scans showed that the cell of J-1 maintained integrity in BDE209-Cd combined pollution system, which indicated the J-1 was strong tolerance to the kind of combined pollution.The result of enzymatic degradation showed that the internal and external enzyme both could degrade BDE209, but the intracellular enzyme was more effective. The environmental factors such as pH, temperature, and dissolved oxygen could affect the activity of extra-cellular enzyme. A certain concentration of Cd could improve the enzymatic degradation. The analysis degrading of products by FT-IR and GC-MS showed that BDE209 was transformed into octa-BDEs by broking off the Br on the benzene ring with the action of microorganisms. At the same time, some oxygen groups such as hydroxyl, carboxyl also produced.更多还原