Development of Colorimetric-Based Whole-Cell Biosensor for Organophosphorus Compounds by Engineering Transcription...

Area of Science:

• Biotechnology
• Environmental Science
• Chemical Engineering

Background:

• Colorimetric whole-cell biosensors offer easy signal visualization but have higher detection limits.
• Bioluminescence- and fluorescence-based biosensors generally exhibit lower detection limits.
• Organophosphate pesticides pose environmental and health risks, necessitating sensitive detection methods.

Purpose of the Study:

• To reduce the detection limit of a colorimetric whole-cell biosensor for organophosphate pesticides.
• To engineer the transcription regulator DmpR using directed evolution to enhance biosensor performance.
• To improve the sensitivity of colorimetric detection for phenolic organophosphate pesticides.

Main Methods:

• Directed evolution was applied to the transcription regulator DmpR.
• Mutants were selected based on enhanced expression of a promoter fused to mRFP1.
• The engineered biosensor's response to parathion was evaluated at varying concentrations and incubation times.

Main Results:

• Two superior mutants, DM01 and DM12, were identified.
• These mutants produced visible red coloration in the presence of parathion as low as 10 μM.
• Detection was achieved after 6 hours of induction at 30 °C.

Conclusions:

• Engineering transcription regulators in the sensing domain can significantly improve whole-cell biosensor properties.
• Directed evolution is an effective strategy for reducing the detection limits of colorimetric biosensors.
• The developed biosensor shows promise for the sensitive colorimetric detection of organophosphate pesticides.