Enhanced mercury biosorption by bacterial cells with surface-displayed MerR.
The metalloregulatory protein MerR, which exhibits high affinity and selectivity toward mercury, was exploited for the construction of microbial biosorbents specific for mercury removal. Whole-cell sorbents were constructed with MerR genetically engineered onto the surface of Escherichia coli cells by using an ice nucleation protein anchor. The presence of surface-exposed MerR on the engineered strains enabled sixfold-higher Hg(2+) biosorption than that found in the wild-type JM109 cells. Hg(2+) binding via MerR was very specific, with no observable decline even in the presence of 100-fold excess Cd(2+) and Zn(2+). The Hg(2+) binding property of the whole-cell sorbents was also insensitive to different ionic strengths, pHs, and the presence of metal chelators. Since metalloregulatory proteins are currently available for a wide variety of toxic heavy metals, our results suggest that microbial biosorbents overexpressing metalloregulatory proteins may be used similarly for the cleanup of other important heavy metals.
Bae
Weon
W
Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
Wu
Cindy H
CH
Kostal
Jan
J
Mulchandani
Ashok
A
Chen
Wilfred
W
D000327:Adsorption; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods; D008628:Mercury / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C051124:MerR protein, Bacteria; C063113:ice nucleation protein; D008628:Mercury