Engineering an Optogenetic pH-Modulator in Bacteria

Area of Science:

• Synthetic Biology
• Microbial Engineering
• Biochemical Engineering

Background:

• Naturally occurring organisms regulate extracellular pH, a capability underexplored in synthetic biology.
• Developing synthetic systems for dynamic pH control is crucial for advanced biological applications.

Purpose of the Study:

• To engineer a microbial system capable of switching between high and low extracellular pH states with minimal human intervention.
• To explore the potential of synthetic biology for dynamic and reversible pH control.

Main Methods:

• Constructed a genetic circuit with a light-inducible promoter for recombinant urease production.
• Incorporated a urease degradation tag to expedite the transition from high to low pH.
• Optimized environmental factors including media composition, replenishment rate, and light exposure patterns.

Main Results:

• The engineered system successfully switched between high and low pH states.
• The system demonstrated continuous cycling for up to 14 days with minimal performance degradation.
• Urease production led to pH increase via urea hydrolysis, while native metabolism lowered pH upon cessation of urease production.

Conclusions:

• The study demonstrates a novel synthetic approach for dynamic extracellular pH control in an engineered living system.
• The findings highlight challenges and potential solutions for implementing such systems beyond controlled laboratory settings.
• This work advances the field of synthetic biology by providing a robust, self-regulating pH control mechanism.