基于芽孢杆菌细胞重编程的重金属捕捉机理研究

项目名称： 基于芽孢杆菌细胞重编程的重金属捕捉机理研究

项目编号： No.31300111

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 汪洋

作者单位： 南京理工大学

项目金额： 22万元

中文摘要： 微生物吸附技术在污水重金属处理方面具有广阔的前景，但剩余污泥中细胞积累的重金属难以回收极易造成二次污染，如何控制剩余污泥并有效回收重金属已成为亟待解决的问题。本项目立足于前期工作中对PHB-MT（聚羟基丁酸酯-金属硫蛋白）纳米生物材料螯合沉淀重金属离子的研究，提出利用细菌分泌的纳米颗粒捕捉重金属的策略，通过细胞编程使菌体完成重金属捕捉功能后发生自裂解，从源头控制剩余污泥的产生。本研究拟采用独创的染色体编辑系统构建锤头状核酶第二茎环的随机突变库，利用抗性基因筛选特异性结合重金属离子的核糖开关(Riboswitch)用以重编程芽孢杆菌，使其灵敏感应重金属离子并相应分泌出PHB-MT螯合沉淀重金属离子，在沉淀完毕后开启细胞凋亡程序。进一步利用温敏型内含肽控制PHB与MT的分离，通过pH梯度洗脱回收与MT结合的重金属离子。本项目将为人工核糖开关研究与细胞功能调控提供新的思路。

中文关键词： 芽孢杆菌；核糖开关；金属硫蛋白；重金属；细胞重编程

英文摘要： Biosorption of heavy metals (HM) by bacteria has attracted more and more concern due to the low cost and high efficiency. However, the large amount of excess activated sludge produced by biosorption treatment tends to cause the secondary pollution because of their high content of heavy metals. To solve this problem, and meanwhile improve the biosorption efficiency, we aim to establish a Riboswitch-based heavy metal sensing system and thereby reprogram Bacillus strains to detect the heavy metal ions and precipitate them by secreting heavy metal biosorbent, and after that initiate self-lysis to control the production of activated sludge. Our proposed work is based on our recent work on the establishment of the Bacillus genome editing system, as well as the discoveries that the PHB nanoparticle-displayed long metallothioneins chelate and precipitate heavy metals with high efficiency. The key issues for this project are the design of heavy metal biosensing system, and the fine control of the heavy metal capture system and cell lysis system by the heavy metal recognition signals. We will employ the genome editing technique that we have recently developed to generate the random mutation library of the hammerhead ribozyme, in order to screen for heavy metal ion specific riboswitches. The reporter genes, spectrometry, a

英文关键词： Bacullus；Riboswitch；Metallothionein；Heavy metal；Cell reprogramming