Co-expression of methyl parathion hydrolase TCP degrading genes in genetically engineered bacterium

摘要

Organophosphorus compounds are the most widely used insecticides, accounting for an estimated 38% of total pesticides used globally. Chlorpyrifos is known for its significant use in agriculture; although chlorpyrifos is defined as a moderately toxic substance, its residues create detrimental effects to the environment. The intermediate metabolite of chlorpyrifos, 3, 5, 6-trichloropyridinol (TCP), is strongly resistant to microbial degradation, making its toxicity to the environment much more significant than chlorpyrifos itself. Unfortunately, the environmental and toxicological problems of TCP is not internationally and domestically consistent. It is agriculturally important to determine the degradation pathway of chlorpyrifos, detect its microbial metabolites, and subsequently find efficient methods to repair chlorpyrifos contaminated soil. In order to degrade chlorpyrifos and its intermediate metabolite TCP simultaneously, the methyl parathion hydrolase gene (mpd) and the TCP degrading gene (tcp3A) were connected to plasmid pET-Duet to generate plasmid pETDuet-mpd-tcp3A. The plasmid pETDuet-mpd-tcp3A was then inserted into E.coli BL21 (DE3) to construct a genetically engineered strain, capable of the co-expression of methyl parathion hydrolase and TCP hydrolase. This study provides an efficient strategy to biodegrade chlorpyrifos and TCP by the construction of a genetically engineered strain of E. coli. Using the initial enzyme to degrade chlorpyrifos and TCP, the degradation rate can reach 68.8% and 47.9% in 100 minutes, respectively.