Escherichia coli to decompose polluted water and sludge By 刘琰，肖琦，邱思，金鑫 2008.3.2 Escherichia coli to decompose polluted water and sludge
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
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
Biological uncoupling: 1) Change components of the respiratory chain of E.coli 2) Change proton gradient 3) Mutate the F1F0 ATP synthase
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)
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
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。
How to express UCP1 in E. coli? Signal peptide Avoid of aggregation Activator: free fatty acid? Cofactor: CoQ?
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
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
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