Genetically engineered bacteria: electrochemical sensing systems for antimonite and arsenite

Area of Science:

• Environmental Science
• Microbiology
• Biotechnology

Background:

• Antimonite and arsenite are toxic metalloids with significant environmental and health implications.
• Developing selective and sensitive detection methods for these ions is crucial for environmental monitoring and remediation.

Purpose of the Study:

• To investigate and characterize a bacterial sensing system for the selective detection of antimonite and arsenite.
• To engineer a genetically modified bacterial strain for biosensing applications.

Main Methods:

• Genetic engineering of bacteria using a plasmid containing the beta-galactosidase reporter gene under the control of the ars operon promoter.
• Co-expression of the ArsR regulatory protein to control reporter gene expression.
• Electrochemical monitoring of beta-galactosidase activity using p-aminophenyl beta-D-galactopyranoside substrate.

Main Results:

• The engineered bacterial system demonstrated selective response to antimonite and arsenite.
• A lesser response was observed for arsenate, with no significant cross-reactivity to phosphate, sulfate, nitrate, or carbonate.
• Electrochemical detection provided a sensitive measure of enzyme activity.

Conclusions:

• The developed bacterial sensing system offers a selective and sensitive method for detecting antimonite and arsenite in environmental samples.
• This biosensor holds potential for real-time monitoring and risk assessment of arsenic and antimony contamination.
• Further optimization could expand its application for detecting other metalloids.