Microbial biosensor for detection of methyl parathion using screen printed carbon electrode and cyclic voltammetry

Area of Science:

• Biotechnology
• Electrochemistry
• Environmental Science

Background:

• Organophosphorus pesticides pose environmental and health risks.
• Developing sensitive and rapid detection methods is crucial for monitoring pesticide levels.
• Recombinant Escherichia coli expressing organophosphorus hydrolase offers potential for biosensor applications.

Purpose of the Study:

• To develop a novel biosensor for the detection of methyl parathion.
• To immobilize recombinant Escherichia coli cells on a screen-printed carbon electrode (SPCE).
• To characterize the performance of the developed biosensor for methyl parathion analysis.

Main Methods:

• Immobilization of whole cells of recombinant Escherichia coli on SPCE using glutaraldehyde.
• Electrochemical characterization using cyclic voltammetry.
• Detection of methyl parathion based on the redox behavior of p-nitrophenol, a hydrolysis product.
• Scanning Electron Microscopy (SEM) for studying immobilized cells.

Main Results:

• The biosensor successfully detected methyl parathion through the electrochemical signal of p-nitrophenol.
• A linear relationship was observed between methyl parathion concentration and oxidation current.
• The detection range was established between 2 and 80 μM with a small sample volume requirement (20 μl).
• The immobilized SPCE showed good reusability, with 80% activity retained after 32 reactions.

Conclusions:

• The developed biosensor is effective for sensitive and quantitative detection of methyl parathion.
• Immobilization of recombinant E. coli on SPCE provides a stable and reusable platform for pesticide monitoring.
• This biosensor technology holds promise for environmental monitoring and food safety applications.