摘要多氯联苯(polychlorinated biphenyls，PCBs) 是环境中典型的持久性氯代有机污染物。采用污染区原生固氮蓝藻作为先锋物种对PCBs进行脱氯降解是一种新颖的原位生物修复方法。本研究以浙江台州多氯联苯污染地区水稻土中分离所得的固氮蓝藻Nostoc PD-2为材料，采用无氯培养体系研究电子供体二硫苏糖醇(DTT)对功能藻种降解2,4,4'-三氯联苯(PCB28)的影响。结果表明：脱氯功能蓝藻Nostoc PD-2对PCB28：具有耐受性和降解作用。在向降解体系中添加浓度为10μg/L，100μg/L和1000μg/L的外源电子供体DTT后，PCB28降解百分比从64。7%分别上升到83。8%；在添加100μg/L DTT条件下暴露0。5d和9d后PCBs降解百分比达到30。8%和90。2%，RT-PCR结果显示，添加100μg/L DTT条件下藻种双加氧酶基因和细胞色素b6f复合体铁硫蛋白基因在PCB28暴露6d后的表达量分别上调了40。9倍和28。4倍。本研究证实电子供体DTT对脱氯功能蓝藻Nostoc PD-2降解多氯联苯具有促进作用，且呈明显的剂量-效应和时间-效应关系，该降解效应与藻细胞内双加氧酶基因和细胞色素b6f复合体铁硫蛋白基因的表达有关。该研究可以在PCBs污染区将脱氯功能蓝藻Nostoc PD-2应用到原位生物修复提供可能。74675

Abstract Polychlorinated biphenyls (PCBs) are the typical persistent organic pollutants (POPs) in the environment。 Using the functional cyanobacterium to dechlorinate plays an important role in PCBs transformation．A new kind of dechlorination function cyanobacterium Nostoc PD-2 was isolated from the paddy soils in Taizhou of Zhejiang Province as the experimental material to study the dechlorinated effects on PCBs by adding the dithiothreitol (DTT) in the chlorine free culture system。 It was proved that the dechlorination functional cyanobacterium Nostoc PD-2 can not only tolerate 2,4’,4-Trichlorobiphenyl(PCB28), but also has the degradation ability for PCB28。 Comparing with the control，adding can make the degradation percentage range from 64。7% up to 83。8%, respectively。 Furthermore, adding 100μg/L DTT in the culture system for 0。5 and 9 days, the degradation percentage can reach to 30。8% and 90。2%。 The RT-PCR results showed that the expressions of dioxygenase gene and cytochrome b6f complex iron-sulfur protein gene increased by 40。9 and 28。4 folds with 100μg/L DTT in the culture system for 6 days。 It is clearly demonstrated that DTT can promote the dechlorinated effects of Nostoc PD-2 on PCB28 with a significant dose and time-response effect。 The study provides a new idea for how to use the dechlorination functional cyanobacterium Nostoc PD-2 in the bioremediation of PCBs polluted paddy soils。

毕业论文关键词：二硫苏糖醇；2,4,4'-三氯联苯；降解；脱氯功能蓝藻Nostoc PD-2

Keyword: dithiothreitol；2,4,4’-trichlorobiphenyl；degradation；dechlorination functional Nostoc PD-2

目    录

0 引言 4

1 材料与方法 5

1。1 实验藻种的分离和培养 5

1。2 主要化学试剂及仪器 5

1。3 实验方法 5

1。3。1 功能藻种细胞中叶绿素a的分析方法 5

1。3。2 不同浓度DTT对PCB28降解影响的暴露实验 6

1。3。3 DTT对降解促进的动力学暴露方法