Expression and subcellular localization of organophosphate hydrolase in acephate-degrading Pseudomonas sp. strain Ind01 and its use as a potential biocatalyst for elimination of organophosphate insecticides

Abstract

Organophosphate hydrolase (OPH), the product of an organophosphate-degrading (opd) gene cloned from Brevundimonas diminuta, hydrolyses the triester linkage found in neurotoxic organophosphate (OP) insecticides and nerve agents. Despite the fact that OPHs have a broad substrate range, OP compounds with a P-S linkage, such as insecticides like acephate, are poor substrates for the enzyme. Expression of OPH in acephate-utilizing Pseudomonas sp. Ind01 generated a live biocatalyst capable of degrading a wide range of OP insecticides. The heterologously expressed OPH, which is a substrate of twin arginine transport (Tat) pathway, successfully targeted to the membrane of Pseudomonas sp. Ind01. The membrane-associated OPH had a size that coincided with the mature form of OPH (mOPH), suggesting successful processing and targeting of the expressed OPH to the membrane. Pseudomonas sp. Ind01 expressing OPH degraded a variety of OP insecticides besides using acephate as sole carbon source.

Significance and impact of the study: A biocatalyst capable of degrading a wide range of organophosphate (OP) insecticides was generated by expressing an organophosphate degradation gene in Pseudomonas sp. Ind01 involved in mineralization of acephate. The biocatalyst can be used to eliminate a wide range of OP insecticide residues from the environment.