Effect of ambient conditions on simultaneous growth and bioaccumulation of mercuric ion by genetically engineered E. coli JM109

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• 作者：Xu Deng ; Yangchun Zheng and Qingbiao Li
• 关键词：Genetically engineered E. coli ; Mercuric ion ; Wastewater ; Bioaccum ulation
• 刊名：Journal of Hazardous Materials
• 出版年：2006
• 出版时间：21 August 2006
• 年：2006
• 卷：136
• 期：2
• 页码：233-238
• 全文大小：486 K

文摘

Genetically engineered E. coli JM109, namely M1, which expressed both Hg²⁺ transport system and metallothionein, was tested for its capability of simultaneous growth and bioaccumulation of Hg²⁺ under low nutritional circumstances. The influential factors of ambient conditions, e.g. initial concentrations of mercuric ion, ionic strength, the presence of metal chelators and other coexisting metal ions were investigated. Hg²⁺ bioaccumulation behavior of M1 proved to be well coupled with its growth. NaCl was essential to the growth of M1. Of all tested NaCl concentrations, 0.04 mol/L was optimal. The presence of 0.1 mol/L CaCl₂ or MgCl₂ could promote the growth of M1 and keep the Hg²⁺ removal ratio high, but the growth of M1 was inhibited seriously as the concentration of CaCl₂ or MgCl₂ reached 0.3 mol/L. Chelator EDTA had a significant influence on M1 growth and Hg²⁺ bioaccumulation, while the effect of citratio was little. The presence of other coexisting metal ions inhibited the growth of M1. The influential order was as follows: Cd²⁺ > Zn²⁺ ≥ Cu²⁺ > Pb²⁺ > Ni²⁺. However, only Cd²⁺ and Cu²⁺ posed obviously adverse effects on Hg²⁺ bioaccumulation during the SG&B process.