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Hg 2+ Removal by Genetically Engineered Escherichia coli in a Hollow Fiber Bioreactor
Author(s) -
Chen ShaoLin,
Kim EunKi,
Shuler Michael L.,
Wilson David B.
Publication year - 1998
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp980072i
Subject(s) - bioreactor , bioaccumulation , bioremediation , chemistry , kinetics , escherichia coli , metal ions in aqueous solution , biodegradation , chromatography , metal , environmental chemistry , contamination , biochemistry , biology , organic chemistry , ecology , physics , quantum mechanics , gene
Escherichia coli cells engineered to express an Hg 2+ transport system and metallothionein accumulated Hg 2+ effectively over a concentration range of 0.2–4 mg/L in batch systems. Bioaccumulation was selective against other metal ions and resistant to changes in ambient conditions such as pH, ionic strength, and the presence of common metal chelators or complexing agents (Chen, S.‐L.; Wilson, D. B. Appl. Environ. Microbiol. 1997 , 63, 2442–2445; Biodegradation 1997 , 8, 97–103). Here we report the characterization of the bioaccumulation system based on its kinetics and an isotherm. Bioaccumulation was rapid and followed Michaelis−Menten kinetics. A hollow fiber bioreactor was constructed to retain the genetically engineered cells. The bioreactor was capable of removing and recovering Hg 2+ effectively at low concentrations, reducing a 2 mg/L solution to about 5 μg/L. A mathematical equation that quantitatively described Hg 2+ removal by the bioreactor provides a basis for the optimization and extrapolation of the bioreactor. The genetically engineered E. coli cells and the bioreactor system have excellent properties for bioremediation of Hg 2+ ‐contaminated environments.