Construction and Improvement of 2,4-Dinitrotoluene-Inducible Biosensor in Escherichia col

Abstract

2,4-Dinitrotoluene (2,4-DNT) is one of the most widely distributed explosives in soil with buried landmines. Because this compound permeates slowly through mine casing and diffuses the soil, DNT can serve as a potential indicator for buried land mines. To construct a DNT biosensor with 2,4-DNT inducible GFP expression system, gfp+ gene was expressed under the control of a yqjF promoter (PyqjF) on plasmid. The promoter was known to be activated by tri-hydroxy toluene (THT), a metabolite of DNT. However, detailed mechanisms of the induction are not well known. Using Tn5 mutant library with the biosensor plasmid to screen genes associated with degradation pathway of DNT into THT, we separated mutant strains showing higher GFP expression than wild type E. coli after DNT treatment. In addition to that, we will perform the screening of genes positively involved in degradation of DNT into THT by the expression of ASKA library, a complete set of ORF clones of E. coli. Finally, we are expected to improve the biosensor system by engineering DNT-degradation related genes.