Freeze-dried recombinant bacteria for on-site detection of phenolic compounds by color change.
We herein report the development of a recombinant bacterial biosensor for the rapid and easy detection of phenolic compounds in the field. A plasmid was designed to encode a beta-galactosidase reporter gene under the control of capR, an activator involved in phenolic compound degradation. The construct was transformed into Escherichia coli, and transformed cells were stored after being freeze-dried in the presence of sucrose. For detection of phenolic compounds, the cells were rehydrated, and used instantly, without any growth step. In the presence of 0.1 microM-10mM phenol, we observed a red color from hydrolysis of chlorophenol red beta-D-galactopyranoside (CPRG) or an indigo color from hydrolysis of X-galactopyranoside (X-gal). Other phenolic compounds could be detected by this system, including catechol, 2-methylphenol, 2-chlorophenol, 3-methylphenol, 2-nitrophenol, and 4-chlorophenol. These results suggest that this novel bacteria biosensor may be useful for easy, on-site detection of phenolic compounds without the need for unwieldy equipment or sample pretreatment. Indeed, biosensor systems involving beta-galactosidase-expressing freeze-dried recombinant bacteria could prove useful for the in situ detection of many more compounds in the future.
Shin
Hae Ja
HJ
Environmental Engineering Major, Division of Applied Bioengineering, Dongseo University, Busan 617-716, Republic of Korea. hjshin@dongseo.ac.kr
Park
Hoo Hwi
HH
Lim
Woon Ki
WK
D015374:Biosensing Techniques / Q000379:methods*; D002733:Chlorophenols / Q000032:analysis / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005612:Freeze Drying; D005697:Galactosides / Q000032:analysis / Q000378:metabolism; D017930:Genes, Reporter; D005818:Genetic Engineering / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000378:metabolism; D010636:Phenols / Q000032:analysis*; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis; D014866:Waste Products / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D002733:Chlorophenols; D005697:Galactosides; D007211:Indoles; D010636:Phenols; D011994:Recombinant Proteins; D012989:Soil Pollutants; D014866:Waste Products; D014874:Water Pollutants, Chemical; C074184:chlorophenol red galactopyranoside; D001616:beta-Galactosidase; C044888:5-bromo-4-chloro-3-indolyl beta-galactoside