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Genetically modified bacteria

Tailor-made design of bacterial strains

The advent of genetic engineering and synthetic biology now makes it possible to modify the genome of microorganisms in order to confer new properties on them, to optimize some already present, or to study specific genes. In this context, Smaltis has developed a number of tools to modify the genome of bacteria in a tailor-made approach.

Our offer

We propose to build genetically modified bacterial strains, using methods adapted to each project, allowing us to modify the bacterial genomes, with a single nucleotide substitution approach.

-Guarantees: absence of scar and resistance cassette
-Quality control: PCR and Sanger sequencing
-Deliverables: genetically modified strains (vials or conservation agar)

Today, our techniques have proven their efficiency in different bacterial species. Do not hesitate to contact us to know our possibilities.


Genetic modification of bacteria is used in many applications such as fundamental research to study the interaction of compounds with bacteria, the evaluation of the functionality of a gene, the use of fluorescent or luminescent strains in a diagnostic context…
The use of bacterial mutants is also very useful for bioproduction in order to optimize bioprocesses: improvement of productivity, elimination of contaminant production, simplification of USP and DSP steps…
Other projects also require the use of genetically modified bacteria, such as the evaluation of resistance mechanisms to antimicrobial molecules, or the reduction of the virulence of a strain to improve its level of safety before its marketing. 


Gene deletion

Deletion of a gene (CDS) or any specific DNA sequence giving the possibility of several applications such as:
      – The study of the functionality of a gene or protein of interest
      – The identification of gene regulation pathways

Example: construction of a BL21 E. coli strain, deleted in DE3 phage-sequence
Available Mutant: BL21∆DE3

Gene replacement

Replacement of a target gene with another gene of interest without changing the initial genetic environment.
Replacement of a gene of interest with a bioluminescent reporter gene, such as Green Fluorescent Protein (GFP), luxCDABE operon, or mCherry fluorescent protein, allows to study directly the modulation of gene expression, without resorting to real-time PCR technology, by quantifying emitted light. 

Example: replacement of a virulence gene of P. aeruginosa PAO1 strain with the Green Fluorescent Protein (GFP) coding gene.

Gene insertion

Insertion of DNA fragments directly into the chromosome of strains, thus creating new metabolic pathways.
These chromosome insertions are utterly stable and do not require any selection pressure (antibiotic or other) to be maintained in the long time. The creation of such strains may be considered a real alternative to the use of expression plasmids to produce recombinant proteins.
We can also “tag” strains by inserting a short DNA sequence in a specific spot of the chromosome, in order to differentiate them among other strains of the same species.

Example: creation of a bank of glow and fluorescent strains from so-called ESKAPE species (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter Baumannii, Pseudomonas aeruginosa and Enterobacter).

Mutagenesis directly on the chromosome

In order to check the impact of a mutation on the expression of genes or the functionality of proteins of interest, we are able to modify your chosen nucleotides directly on the chromosome of a strain. The insertion of stable mutation will allow not only to study the functionality of the variants of the same protein, but also to optimize the functionality of an enzyme by changing its active site.

Example: modification of specific nucleotides in the coding gene for the AmpC beta-lactamase of P. aeruginosa to assess the impact of potential mutations on the activity of the enzyme.