Escherichia coli to decompose polluted water and sludge

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1 Escherichia coli to decompose polluted water and sludge
By 刘琰，肖琦，邱思，金鑫 Escherichia coli to decompose polluted water and sludge

2 Background: 污水生物处理技术——活性污泥法 剩余污泥的处理问题 筛选能特异性降解的微生物 提高微生物的降解效率

3 氧化磷酸化解偶联： 解偶联是指将呼吸链的氧化作用与磷酸化作用分开的现象。在代谢物的氧化过程中ATP不产生或产生量减少，剩余能量以热能的形式放出。在解偶联的情况下，微生物为了获得满足生长需求的能量，势必会增大对营养物质的代谢消耗。 chemical uncoupling VS biological uncoupling

4 Biological uncoupling:
1) Change components of the respiratory chain of E.coli 2) Change proton gradient 3) Mutate the F1F0 ATP synthase

5 1) Respiratory chain of E. coli
Different dehydrogenases (NADH dehydrogenases Ⅰ,Ⅱ) Different teminal oxidases or reductases (Quinol oxidases bo3-type & bd-type) Linked by quinones (Ubiquinone)

6 NDH 1 (nuo) 2 H+/e- NDH 2 (ndh) 0 H+/e-
bo-type oxidase (cyo) 2 H+/e- Quinone NADH O2 NDH 2 (ndh) 0 H+/e- bd-type oxidase (cyd) 1 H+/e- Fig1. A schematic representation of several major components of the aerobic respiratory chain of E.coli

7 2)Change proton gradient
Uncoupling protein(UCP)主要存在于动物及一些高等植物中。当质子从UCP返回膜内而不经过ATP synthase 时，就发生解偶联。

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9 How to express UCP1 in E. coli?
Signal peptide Avoid of aggregation Activator: free fatty acid? Cofactor: CoQ?

10 3) Mutate ATP synthase Uncouple the ATP synthesis and proton transport
Target sites: β,δ etc βS174L: decrease enzyme activity but remain the coupling to proton translocation. can grow by oxidative phosphorylation

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12 Summary 1、敲除 NDH 1, bo-type oxidase 以减少proton pumping
2、表达UCP，改变膜对氢离子的通透性 3、突变ATP synthase，降低ATP的合成

13 Thanks~~