Keywords: waste gas treatment, biofilters, genetically engineered microorganisms, organophosphorus pesticides, methyl parathion, parathion, air pollution, air quality, genetic engineering, Escherichia coli, E coli
Simultaneous removal of parathion and methyl parathion by genetically engineered Escherichia coli in a biofilter treating polluted air
A biofilter inoculated with a genetically engineered Escherichia coli strain was successfully applied to treat air streams containing a mixture of parathion and methyl parathion (MP). Average removal efficiencies of 95.2% for parathion and 98.6% for MP were obtained during the overall operation period. Compared with conventional biofilters, the biofilter inoculated with the engineered E. coli BL21 was far more effective, especially in the initial stages. Parathion and MP could be treated simultaneously within one biofilter. Metabolite analysis revealed that parathion and MP were hydrolysed to p-Nitrophenol (PNP). Additionally, nitrate and sulphate were detected during the biofilter operation. The biofilter performance and microbial community were also assessed and characterised.