A novel biosensor for the detection of organophosphorus (OP)-based pesticides using organophosphorus acid anhydrolase (OPAA)-FL variant.

In this study, recombinant expression of the OPAA-FL variant in Escherichia coli was performed, purified, and subsequently tested for activity against ethyl paraoxon. OPAA-FL variant showed its optimum activity at pH 8.5 and 50 °C. Colorimetric and fluorometric assays were used for estimation of ethyl paraoxon based on p-nitrophenol and fluorescein isothiocyanate (FITC) fluorescence intensity, respectively. Colorimetric and fluorometric assay estimation indicates that ethyl paraoxon can be estimated in the linear range of 0.01 to 1 mM and 0.1 to 0.5 mM, with LOD values 0.04 mM and 0.056 mM, respectively. Furthermore, the OPAA-FL variant was immobilized into alginate microspheres for colorimetric detection of ethyl paraoxon and displayed a linear range of 0.025 to 1 mM with a LOD value of 0.06 mM. KEY POINTS: • Biosensing of paraoxon with purified and encapsulated OPAA-FL variant. • Colorimetric and fluorometric biosensing assay developed using OPAA-FL variant for paraoxon. • First report on alginate encapsulation of OPAA-FL variant for biosensing of paraoxon. Graphical abstract. PMID: 33191461 [PubMed - as supplied by publisher]
Source: Applied Microbiology and Biotechnology - Category: Microbiology Authors: Tags: Appl Microbiol Biotechnol Source Type: research