Purification and characterization of a novel p,p’-DDT dehalogenase from Aeromonas sp. strain MY1

Abstract

Although dichlorodiphenyltrichloroethane (DDT) occupies a prominent position for its recalcitrance in the environment which led to its ban by the Stockholm Convention. This pesticide is still unregulated used in low and middle-income countries, which contributes to the global burden of this hazardous contaminant. In the recent time, biological approach has been proven to be effective and environmentally safer for the decontamination of the residual DDT. In this research, we reported a gel-purified p,p’-DDT dehalogenase from Aeromonas sp. strain MY1, revealing a single band with a molecular weight of approximately 37 kDa. The dehalogenase was unique for its capability to release chloride ions from p, p’-DDT substrate with optimum dechlorination activity at pH 8.0 and 35°C. The enzyme followed Michaelis-Menten’s kinetics and measurement of its initial velocities with various p,p’-DDT concentrations showed a Km of 27.05 μmol L-1 and Vmax of 476.19 μmol L-1 min-1. However, the enzyme lost its dechlorination activity in the presence of Ag2+ and Hg2+ This dehalogenase could pave a way for the effective decontamination of p,p’- DDT contaminated environment, suggesting its potentials for p,p’-DDT bio-cleansing applications.