A comparative study on degradation of complex malathion organophosphate using of Escherichia coli IES-02 and a novel carboxylesterase

Malathion organophosphates considered as the major constituent of herbicides, pesticides and insecticides. Extensively used in agricultural, horticultures and for numerous household applications contributes to precedence organic pollutants leading antagonistic effects on human health and environment. Therefore detoxification of malathion from contaminated site is of general interest. Simultaneously it is very emerging to isolated novel indigenous microbial strains from contaminated site with a record of pesticide application. In this study Escherichia coli IES-02 isolated from malathion contaminant effluent and the strain showed maximum efficiency in malathion degradation that utilized it as the sole source of carbon. Carboxylesterase (33.0, 30.0, 28.0 kDa) were purified (1685.71 U/mg) from Escherichia coli IES-02 showed significant results in malathion degradation approximately 81% within 20 min as compared with Escherichia coli IES-02 cells within 4 h (99.0 to 95.0%) into monocarboxylic acid and diacid derivatives. The generation time of Escherichia coli was also observed at 60 min with 0.1 ppm, 68 min with 0.5 ppm, 74.5 min with 2.0 ppm and 91.37 min with 50 ppm of malathion. The degradation rate and transformation metabolites were estimated by Gas Chromatography-Mass Spectrometry respectively. Malathion metabolites pathway proposed in this study which revealed the potential application against lethal environmental pollution.