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Engineering quorum-sensing circuits in Synechococcus elongatus PCC 7942 towards self-inducible systems
Emmanuel J Kokarakis1, María Santos-Merino2, Sajjad Ghaffarinasab3
1Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, United States; MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, United States.
Metabolic Engineering
|July 27, 2025
Summary
Engineered cyanobacteria now feature quorum sensing (QS) for controlled gene expression. This breakthrough enhances biomass recovery, paving the way for scalable bioproduction applications.
Area of Science:
- Synthetic biology
- Microbial biotechnology
- Cyanobacterial research
Background:
- Cyanobacteria hold significant potential for sustainable bioproduction.
- Current limitations include poor adaptation to bioreactors and challenges in scaling biomass growth and harvesting.
- Auto-induction systems are needed to coordinate gene expression with population density.
Purpose of the Study:
- To explore quorum sensing (QS) pathways from heterotrophic microbes for auto-induction of gene expression in cyanobacteria.
- To engineer Synechococcus elongatus PCC 7942 to produce and respond to acyl-homoserine lactone (AHL) signals.
- To demonstrate improved biomass recovery using a QS-controlled system.
Main Methods:
- Integrated genetic modules for AHL signal production and detection in Synechococcus elongatus.
- Utilized a hybrid QS system combining Lux (Vibrio fischeri) and Las (Pseudomonas aeruginosa) components.
- Coupled the QS pathway to the expression of a cell division inhibitor (cdv3) gene.
Main Results:
- Demonstrated dose-dependent and population density-responsive gene expression in Synechococcus elongatus.
- Identified an optimal hybrid QS system that mitigates toxicity.
- Achieved late-phase cell elongation, increased cell sedimentation, and improved biomass recovery.
Conclusions:
- Developed a functional quorum sensing-based auto-induction system in cyanobacteria.
- This system enables population density-responsive gene expression and enhanced biomass recovery.
- Provides a foundation for advancing cyanobacterial biotechnology and scalable bioproduction.
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