A Novel Whole-Cell Biosensor for Bioavailable Antimonite in Water and Sediments

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Antimony (Sb) is an emerging environmental contaminant.
• Accurate on-site speciation analysis of Sb(III) is crucial for assessing its bioavailability and toxicity.
• Existing whole-cell biosensors (WCBs) for Sb(III) face challenges due to a lack of specific recognition components.

Purpose of the Study:

• To develop a novel Sb(III)-specific whole-cell biosensor (WCB).
• To enhance the sensitivity and specificity of WCBs for Sb(III) detection.
• To enable on-site measurement of Sb(III) bioavailability in environmental samples.

Main Methods:

• Constructed a novel Sb(III)-specific WCB using an Sb(III) transcriptional regulator (antR) and its cognate promoter (P).
• Inserted an additional antR gene downstream of the Sb(III)-inducible promoter to prevent promoter leakage.
• Integrated the WCB with a tea-bag design for on-site field applications.

Main Results:

• The modified WCB demonstrated an order of magnitude improvement in sensitivity, with a detection limit of 0.009 μM.
• The WCB exhibited high specificity for Sb(III) against interfering ions at concentrations three orders of magnitude higher.
• On-site measurements of Sb(III) bioavailability in natural waters and sediments showed no statistical difference compared to chemical analysis.

Conclusions:

• The addition of regulatory genes effectively prevents promoter leakage and enhances WCB sensitivity.
• The developed Sb(III)-specific WCB is a promising tool for accurate on-site speciation analysis of antimony.
• This approach improves the field applicability and reliability of WCBs for environmental monitoring.