Pesticide degradation by immobilised metalloenzymes provides an attractive avenue for bioremediation

Abstract Although organophosphate (OP) pesticides (e.g., parathion, chlorpyrifos) have revolutionized agriculture leading to a dramatic increase in crop yields they also represent a critical and persistent global pollutant detrimental to both the environment and human health. No environmentally friendly and efficient method to remove such pollutants has yet been brought to market. Here we present an enzyme-based technology that facilitates the efficient conversion of a toxic compound (i.e., the pesticide ethyl-paraoxon) into an essential nutrient (i.e., inorganic phosphate) that supports the growth of crops. The efficiency of the technology relies on the combined action of three OP-degrading metalloenzymes with complementary substrate specificity. The enzymes were immobilised on Ni-NTA coated magnetic nanoparticles (MNPs), which significantly enhanced both their thermal stability (by up to 10 °C) and reactivity (up to three-fold). In a test reaction the half-lives of pesticide degradation and phosphate formation were approximately 2 min and 23 min, respectively. Storage of the enzyme-coated MNPs at 4 °C for up to a year resulted in a less than 10% loss of catalytic efficiency. The modular nature of the technology allows the integration of diverse enzymes with desired catalytic properties and thus provides a simple, reliable and reusable system for the decontamination of polluted environments.