94
phenol. In a study, Turner (2007) developed a whole-cell biosensing system for the
detection of polychlorinated biphenyls by employing the strain Pseudomonas azelaica HBP1. This bacterium contains the hbpCAD genes that are responsible for the
degradation of hydroxylated biphenyls. A regulatory protein encoded by the gene
hbpR located upstream from the hbpCAD genes regulates the expression of these
genes. A strain of E. coli carries a recombinant plasmid consisting of luxAB reporter
gene under the control of HbpR regulatory protein. The detection limits ranging
from 1 × 10
−5
M to 1 × 10
−9
M depend on which para-substituted polychlorinated
biphenyls. Similarly, soil bacterium Ralstonia eutropha ENV307 (pUTK60) is used
for monitoring the polychlorinated biphenyls by inserting the biphenyl promoter
(bphA1/BphS) upstream of the bioluminescence gene (lux CDABE). The minimum
detectable limits for these compounds ranged from 0.15 mg/L for 4-chlorobiphenyl
to 1.5 mg/L for Aroclor.
Bhattacharyya et al. (2005) developed a different set of constitutive and inducible bioreporters to detect chlorinated aliphatic hydrocarbons in groundwater. The
modified Pseudomonas putida TVA8 linearly responds to trichloroethylene. A
detection limit of sensor system was achieved up to 2000 μmol/L. Later, Tecon and
Van der Meer (2008) constructed a biosensor for detecting aromatic hydrocarbon.
The Burkholderia sartisoli RP007 (pPROBE-phn-luxAB) strain detects naphthalene
and phenanthrene in seawater. The modified strain was able to detect hydrocarbon
in seawater with 3 h incubation and detection limit reaching up to 0.17 μM. From
this study, the biosensor could be used as a simple and rapid tool for identifying
hydrocarbons in oil-contaminated sites. Ivask et al. (2001) developed a bacterial
sensor system for detection of methyl mercury compounds. The sensor carried lux
gene as a reporter gene under the control of mercury-inducible regulatory protein
(mer from Serratia marcescens). The sensitivity of the sensor was tested on some
important organomercurial compounds. The lowest detectable concentration was
Vector
Transcription
Cell array
mRNA
E n v ir o n m
e n t a l
P o ll u t a n t
Translation
Reporter
Signal
Signal
detection
F
F F F F F F F F
F
O
H
F F F F F F F
o
o
o
o
o
o
Fig. 4.3 Schematic representation of bioregulator bacterium for specific pollutant
S. Ganesan and N. Vasudevan
phenol. In a study, Turner (2007) developed a whole-cell biosensing system for the
detection of polychlorinated biphenyls by employing the strain Pseudomonas azelaica HBP1. This bacterium contains the hbpCAD genes that are responsible for the
degradation of hydroxylated biphenyls. A regulatory protein encoded by the gene
hbpR located upstream from the hbpCAD genes regulates the expression of these
genes. A strain of E. coli carries a recombinant plasmid consisting of luxAB reporter
gene under the control of HbpR regulatory protein. The detection limits ranging
from 1 × 10
−5
M to 1 × 10
−9
M depend on which para-substituted polychlorinated
biphenyls. Similarly, soil bacterium Ralstonia eutropha ENV307 (pUTK60) is used
for monitoring the polychlorinated biphenyls by inserting the biphenyl promoter
(bphA1/BphS) upstream of the bioluminescence gene (lux CDABE). The minimum
detectable limits for these compounds ranged from 0.15 mg/L for 4-chlorobiphenyl
to 1.5 mg/L for Aroclor.
Bhattacharyya et al. (2005) developed a different set of constitutive and inducible bioreporters to detect chlorinated aliphatic hydrocarbons in groundwater. The
modified Pseudomonas putida TVA8 linearly responds to trichloroethylene. A
detection limit of sensor system was achieved up to 2000 μmol/L. Later, Tecon and
Van der Meer (2008) constructed a biosensor for detecting aromatic hydrocarbon.
The Burkholderia sartisoli RP007 (pPROBE-phn-luxAB) strain detects naphthalene
and phenanthrene in seawater. The modified strain was able to detect hydrocarbon
in seawater with 3 h incubation and detection limit reaching up to 0.17 μM. From
this study, the biosensor could be used as a simple and rapid tool for identifying
hydrocarbons in oil-contaminated sites. Ivask et al. (2001) developed a bacterial
sensor system for detection of methyl mercury compounds. The sensor carried lux
gene as a reporter gene under the control of mercury-inducible regulatory protein
(mer from Serratia marcescens). The sensitivity of the sensor was tested on some
important organomercurial compounds. The lowest detectable concentration was
Vector
Transcription
Cell array
mRNA
E n v ir o n m
e n t a l
P o ll u t a n t
Translation
Reporter
Signal
Signal
detection
F
F F F F F F F F
F
O
H
F F F F F F F
o
o
o
o
o
o
Fig. 4.3 Schematic representation of bioregulator bacterium for specific pollutant
S. Ganesan and N. Vasudevan