Antibiotic-free Selection for E. coli

Moving beyond antibiotic resistance markers

From basic cloning to large-scale biomanufacturing, antibiotic-free plasmid selection and reliable maintenance of genetic constructs are increasingly important in E. coli production systems. Traditional plasmid selection commonly relies on antibiotic resistance genes, but the use of antimicrobial resistance (AMR) markers is facing increasing regulatory and public-health scrutiny.

This regulatory shift is particularly explicit in veterinary biologics. USDA Center for Veterinary Biologics Notice 23-06 states that “newly licensed veterinary biologics should not contain AMR genes”. The USDA also strongly recommends removing AMR genes from currently licensed products and indicates that future measures could include labeling requirements or market removal based on risk assessment.

For companies developing new biological products, replacing antibiotic-resistance selection markers early can therefore help anticipate evolving regulatory expectations and avoid costly process changes later in development.

Syngulon’s antibiotic-free solution

Syngulon has developed a patented bacteriocin-based selection technology that eliminates the need for antibiotic resistance markers.

The system uses a bacteriocin and its corresponding immunity mechanism to create continuous biological selection pressure. Cells maintaining the desired plasmid are protected by the immunity function, while cells that lose the plasmid are selectively eliminated.

The technology is 100% plasmid-based, requiring no modification of the host chromosome and facilitating integration into existing Escherichia coli production platforms.

Key benefits

Antibiotic-free selection
Eliminates antibiotic resistance markers and supports the transition toward AMR-free biomanufacturing.

Robust plasmid maintenance
Continuous biological selection helps maintain the desired genetic construct throughout microbial cultivation.

Production performance
Bacteriocin-based selection can reduce dependence on conventional antibiotic selection and is designed to support efficient microbial fermentation and recombinant product manufacturing.

Genetic stability
Continuous selection limits the expansion of plasmid-free cells and helps control genetic drift during cultivation.

Ease of implementation
The system is entirely plasmid-based and can be introduced without chromosomal engineering, making it compatible with a broad range of E. coli strains and established production workflows.

Minimal disruption of existing production platforms
The plasmid-based system enables antibiotic-free selection with minimal disruption to established industrial hosts, vector backbones and validated production processes.

Applications in E. coli Biomanufacturing

Syngulon’s antibiotic-free plasmid selection technology is designed for applications ranging from research and strain development to industrial biomanufacturing, including:

• recombinant protein production
• plasmid DNA production
• enzymes and other microbial bioproducts
• other E. coli-based production processes requiring stable plasmid maintenance.

A practical response to evolving AMR requirements

AMR genes are increasingly scrutinized not only because of the resistance phenotype they may confer, but also because of their potential for vertical or horizontal transfer.

Syngulon provides manufacturers with an antibiotic-free plasmid selection system that replaces antibiotic-resistance markers while retaining strong plasmid selection pressure and enabling adoption with minimal disruption to established industrial hosts, vector backbones and validated production processes.

Our technology is available to industrial and pharmaceutical partners through non-exclusive licensing.

Learn more in the presentation below

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Explore Syngulon’s other bacteriocin-based technologies for contamination control and therapeutic applications.