E. coli is one of the most widely used expression hosts for the production of recombinant proteins. It is often the first system chosen for producing recombinant proteins due to its advantages over other systems, such as:

  • Inexpensive setup and running costs
  • High recombinant protein production levels 
  • Short timeline from cloning to protein recovery
  • Limited technical knowledge required for culturing
  • Scalability from small (1 mL) to very large culture (>10,000 L) volumes

However, bacterial expression systems are limited in their ability to perform post-translational modifications (PTMs) and facilitate disulphide bond formation. Most proteins require some form of PTM to be produced in their native conformation. Due to the reducing environment of the bacterial cytoplasm, disulphide bond formation can only be achieved by targeting the protein to the oxidative periplasm. Some modern E. coli strains have been developed to overcome some of these limitations (see below).