Constitutive Lactococcus Expression Service

L. lactis expression system can be used to express foreign protein at a high level. The expression system is regulated by constitutive promoters rather than inducers. Creative BioMart now provides expression services based on L. lactis. We will select different expression vectors according to customers' requirements to construct food-grade/non-food-grade expression systems. At present, we have successfully expressed dozens of foreign proteins with a constitutive expression system.

Service Content

Expression procedure and delivery standard of L.lactis constitutive expression system.

Selection of expression system (if the customer provides the expression strain, this step will be omitted. Only the optional host strain of expression plasmid will be provided)
Available expression option	Standard constitutive expression system Food grade constitutive expression system
Construction of expression vector	Deliverable
Gene optimization Subcloning design Synthetic gene Subcloning to vector	1. Gene synthesis report 2. Sequencing validation report 3. Cloning strain containing expression plasmid (optional) 4. Expression plasmid 5. Plasmid instructions
Analysis and identification of protein expression test
Electroconversion Expression test Expression analysis and identification Expand scale	1. Positive expression strains 2. Small test expression process report 3. Images and spectrums obtained from the analysis 4. Small test expression summary
Protein expression and purification
Protein affinity purification (extracellular or intracellular) Identify purified proteins using WB PFM detection (optional) MS detection (optional)	1. Protein purification process report 2. Original picture of protein purification 3. Delivery of protein 4. Western blot (labeled-antibody) 5. Protein fingerprint (optional) 6. Molecular weight of protein mass spectrometry (optional)
Scale-up culture in fermentor
Amplification Culture (10-20l) Amplification Culture (above 50L)	1. Protein purity identification report 2. Finished protein (agreed price according to the results of expression test)

Recommended Host Strains and Plasmids

Here are some recommended host cell strains and plasmids that are suitable for the expression system.

Host strains

Strains	Application
Lactococcus lactis MG1363	Non-food grade
Lactococcus lactis NZ300	Food-grade
Lactococcus lactis NZ1330	Food-grade

Expression plasmid

Plasmids	Application	Features
pNZ124	General broad-host-range	Multiple cloning sites for L. lactis and other lactic acid bacteria; chloramphenicol selection
pNZ2103	Broad-host-range	Gene expression under control of the lacA promoter; for transcriptional fusion; Chloramphenicol selection;
pNZ2015	General broad-host-range	Multiple cloning sites for L. lactis NZ3000; LacF-based selection
pNZ2122	Food grade	Gene expression under control of the lacA promoter for L. lactis NZ3000; For transcriptional fusions; LacF-based selection
pNZ2123	Food grade	Identical to pNZ2122 but with inverted multiple cloning site LacF-based selection
pNZ2125	Food grade	Multiple cloning site appropriate for gene expression into L. lactis strain NZ1330; alr-based selection
pNZ7021	Broad-host-range	Gene expression under control of a strong promoter PpepN; Chloramphenicol selection
pNZ7025	Food grade	gene expression under control of the pepN promoter; alr-based selection. This vector is also designed for translation fusions as described above for the plasmid pNZ7021.

Why Choose Constitutive Lactococcus Expression System

Less endogenous and no exogenous protease
Endotoxin-free expression system
Possible food grade protein expression
No formation of inclusion bodies
No formation of spores
Simple fermentation, scale-up and downstream processing
It is also suitable for bacteria other than lactic acid bacteria

What You Can Do With The Technology

Overexpression of homologous and heterologous genes is used for functional research and a large number of specific gene products are obtained
Metabolic engineering
Proteins are secreted and anchored in the cell membrane
Large-scale production

Constitutive Lactococcus Expression Service

Customers who need our assistance are more than welcome to contact us or submit an online inquiry. Our professional team will provide you with detailed guidance and solution ASAP.

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