Giving the cells what they need when they need it: Biosensor-based feeding control.

Area of Science:

• Biotechnology
• Microbial Physiology
• Process Engineering

Background:

• Traditional bioprocess control relies on environmental parameters, often failing to capture real-time cellular needs.
• Monitoring microbial physiology directly offers a more accurate approach to optimize fermentation performance.

Purpose of the Study:

• To develop and validate a bioprocess control strategy based on microbial physiological behavior.
• To utilize genetically encoded biosensors and online flow cytometry for real-time monitoring.
• To improve fermentation process development time, robustness, and performance.

Main Methods:

• Development of a biosensor using the glnA promoter (glnAp) to monitor nitrogen nutritional status in Escherichia coli.
• Application of the biosensor across various scales, from microplate to 20L bioreactors.
• Creation of an automated bioreactor-flow cytometry interface for continuous monitoring.
• Validation through a fed-batch experiment using biosensor signal for feedback control.

Main Results:

• Demonstrated functionality of the glnAp biosensor for monitoring nitrogen status in E. coli.
• Successful implementation of the automated bioreactor-FCM interface for online population analysis.
• Validated the proposed control strategy by successfully using biosensor signal for nitrogen feeding control.

Conclusions:

• A novel bioprocess control strategy based on direct monitoring of microbial physiological state was successfully developed and validated.
• This cell-centric approach, integrating biosensors and flow cytometry, significantly enhances control over fermentation processes.
• The strategy promises accelerated process development and improved robustness and performance in biomanufacturing.