재조합 미생물 바이오센서를 이용한 chlorotoluene과 nitrotoluene 화합물의 검출

Abstract

Aromatic hydrocarbons are toxic environmental pollutants that are detrimental to the ecosystem and human health. Among them, chlorotoluene and nitrotoluene are toxic to hydrobios and irritate the skin, eyes, and respiratory organs of humans. We herein report the development of recombinant microbial biosensors for cheap and rapid monitoring of chlorotoluene and nitrotoluene compounds. Plasmids were constructed by inserting the xylR regulatory gene for BTEX (benzene, toluene, ethylbenzene, and xylene) degradation into upstream of Po’ (the DmpR activator promoter Po with the deletion of its own upstream activating sequences) or Pu (the cognate promoter of XylR)::lacZ (the β-galactosidase gene) and transformed into Escherichia coli DH5α. In the presence of inducers, the biosensor cells immobilized in agarose developed a red color in 1-2 h due to the hydrolysis of chlorophenol red β-D-galactopyranoside (CPRG), a substrate of β-galactosidase that was expressed by the inducers. Among BTEX, high responses were specifically observed with o-, m-, p-chlorotoluene (0.1 ㎛-100 mM) and o-, m-, p-nitrotoluene (0.1 mM-100 mM). Po’ demonstrated higher responses than those with Pu. The biosensors immobilized in agarose showed good stability after 21 days’ storage at 4℃, and responses in untreated wastewater spiked with chlorotoluene and nitrotoluene, suggesting they can be used to detect compounds in wastewater.