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Selective detection of gold using genetically engineered bacterial reporters
Author(s) -
Cerminati Sebastián,
Soncini Fernando C.,
Checa Susana K.
Publication year - 2011
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.23213
Subject(s) - detection limit , escherichia coli , biosensor , salmonella , reporter gene , bacteria , transgene , genetically engineered , biology , green fluorescent protein , fluorescence , gene , chemistry , biophysics , nanotechnology , materials science , gene expression , biochemistry , chromatography , genetics , physics , quantum mechanics
Salmonella typhimurium harbours a Au‐resistance system whose expression is controlled by GolS, a transcriptional regulator of the MerR family that selectively detects Au with high sensitivity. We developed both Salmonella and genetically engineered Escherichia coli strains as Au‐selective whole‐cell biosensors by coupling the strictly regulated GolS‐dependent golB promoter to the gfp reporter gene. The bio‐reporters were evaluated under different laboratory conditions and calibrated for their use as selective Au detectors. Due to the intrinsic characteristics of the regulatory protein, the transgenic E. coli sensor exhibits low background, high signal‐to‐noise ratio, and improved sensitivity for detection of Au ions in a wide range of concentrations (up to 470 nM) with a calculated detection limit of ∼33 nM (6 µg L −1 or parts per billion) Au(I). The fluorescent Au‐sensing bacteria exhibit also minimal interference by chemically related metals such as Cu or Ag that are commonly found in Au deposits. These highly specific and sensitive Au detectors might allow the development of rapid and robust screening tools to improve discovery and extraction procedures. Biotechnol. Bioeng. 2011;108: 2553–2560. © 2011 Wiley Periodicals, Inc.