Bacterial Expression

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Bacteria is the most popular host of choice for the expression of many proteins as production of heterologous protein in bacteria is easy, time-saving and cost-efficient. A large number of bacterial expression plasmids are also available and suitable for a wide variety of needs. Most commonly used bacterial hosts for protein production include E.coli and Bacillus subtilis.

Advantages:

Simple physiology
Short generation timeline, as bacteria grow and multiply rapidly
Tight control of gene expression with the highest yield compared to other systems - up to 10 % of mass
Broad range of expression levels using different inducer concentrations
Active at low temperature (16ºC) and low sensitivity to media formulation
Availability of vectors with protein fusion tags for purification using low cost affinity supports
Cost effective and scalable bioprocess engineering
Higher rate of success in obtaining soluble proteins

Disadvantages:

Activity. The expressed proteins often do not fold properly, resulting in are biologically inactive.
Toxicity. The synthesized proteins are often toxic to bacteria, preventing the cell cultures from reaching high densities. A solution to this problem is to incorporate an inducible promoter, which may be turned on to transcribe the inserted gene after the culture has been grown.
Modification. Lack of enzymes responsible for post-translational modifications (effect on function of proteins), e.g. if the protein to be expressed is a glycoprotein, there is no apparatus in the bacterium to attach the necessary sugar residues. In this case, mammalian cell expression system is the best choice.

Applications:

Laboratory and large scale recombinant protein expression/purification: optimization of host, expression systems, and downstream processing with the use of our genetic technology.
Whole cell biocatalysis: stable assemblage of metabolic pathways.
Programming therapeutic bacteria expression: antigen expression and display in attenuated pathogenic bacteria.
Expression of heteromultimeric proteins.

Figure 1. High throughput screening process for bacterial expression systems

Please see Creative Biostructure’s cell-free and cell-based expression services.

Reference:

Rachel Chen. Bacterial expression systems for recombinant protein production: E. coli and beyond. Biotechnology Advances. Volume 30, Issue 5, September–October 2012, Pages 1102–1107
Germán L. Rosano and Eduardo A. Ceccarelli. Recombinant protein expression in Escherichia coli: advances and challenges. Front Microbiol. 2014; 5: 172. doi: 10.3389/fmicb.2014.00172