Biosensor for direct determination of fenitrothion and EPN using recombinant Pseudomonas putida JS444 with surface-expressed organophosphorous hydrolase. 2. Modified carbon paste electrode

Abstract

This paper reports a first microbial biosensor for rapid and cost-effective determination of organophosphorus pesticides fenitrothion and EPN. The biosensor consisted of recombinant PNP-degrading/oxidizing bacteria Pseudomonas putida JS444 anchoring and displaying organophosphorus hydrolase (OPH) on its cell surface as biological sensing element and a dissolved oxygen electrode as the transducer. Surfaceexpressed OPH catalyzed the hydrolysis of fenitrothion and EPN to release 3-methyl-4-nitrophenol and p-nitrophenol, respectively, which were oxidized by the enzymatic machinery of Pseudomonas putida JS444 to carbon dioxide while consuming oxygen, which was measured and correlated to the concentration of organophosphates. Under the optimum operating conditions, the biosensor was able to measure as low as 277 ppb of fenitrothion and 1.6 ppm of EPN without interference from phenolic compounds and other commonly used pesticides such as carbamate pesticides, triazine herbicides and organophosphate pesticides without nitrophenyl substituent. The applicability of the biosensor to lake water was also demonstrated.

An overview of detection techniques for monitoring dioxin-like compounds: latest technique trends and their applications

“…66,68,106 The biosensor has been dened by Thevenot et al as "a selfcontained integrated device that is capable of providing specic quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor), which is retained in direct spatial contact with a transduction element". 117 However, little scientic information regarding potential cell-based biosensors for detection of DLCs are available. Theoretically, biosensor techniques are categorized based on their bio-recognition elements being applied.…”

“…114 Biosensors include two major components: the transducer, which converts the event into an electronic signal and the bio-recognition element, which detects the specic contaminants. 72,117 The advantages of a whole cell-based biosensor for sediment or soil samples are its simple measurement, extraction and preparation techniques and low-cost instruments. These elements consist of DNA, antibodies, enzymes, biological receptors, and whole cells.…”

Microbial Biosensors: Engineered Microorganisms as the Sensing Machinery

“…Our group has developed several engineered strains displaying organophosphorus hydrolase (OPH) on the cell surface for the simultaneous hydrolysis of organophosphorous pesticides into p -nitrophenol and its subsequent conversion into electrochemically active intermediates [15,86]. By immobilizing these engineered cells onto a carbon paste electrode, different organophosphorus pesticides can be detected by measuring the corresponding electrooxidation current generated from these intermediates [90]. Similarly, Liu et al displayed xylose dehydrogenase (XDH) on the cell surface using the INP anchor for the detection of D-xylose, a compound of significant interest in genetics, human nutrition, food technology and pharmacology [87].…”

An Organophosphorus Hydrolase-Based Biosensor for Direct Detection of Paraoxon Using Silica-Coated Magnetic Nanoparticles

“…Additionally, low relative CV% (n=6) showed excellent data reproducibility. Moreover, it was revealed that naturally existing compounds in serum did not cause significant interferences in (Table 2) [9,16,[22][23][24][25][26][27][28][29][30][31][32].…”