Recombinant Protein Expression in Bacterial Systems

Recombinant protein expression in bacterial hosts, most notably Escherichia coli, underpins a vast array of research and industrial applications, from enzyme production to therapeutic biologics. The process begins with the design of an expression vector carrying the gene of interest under the control of a suitable promoter, often inducible to allow tight regulation of synthesis. Optimisation of codon usage, messenger RNA stability and ribosome‐binding sites enhances translational efficiency, while fusion tags facilitate protein solubility and streamline purification. Cultivation parameters such as temperature, medium composition and induction timing are calibrated to balance cell growth against metabolic burden. Despite the allure of rapid growth and low cost, bacterial systems frequently contend with misfolding and aggregation of heterologous proteins into inclusion bodies, necessitating refolding protocols or periplasmic targeting to exploit the oxidising environment for disulfide bond formation. Advances in strain engineering, chaperone co‐expression and automated bioprocessing have further refined yields and reproducibility. This confluence of molecular design and process engineering has rendered bacterial platforms indispensable for high‐throughput screening, structural biology and the manufacture of vaccines, diagnostics and speciality enzymes on a global scale.

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Research from all publishers

Recent studies have established a versatile caspase‐based fusion process (CASPON®) for scar‐free tag removal in E. coli, demonstrating broad physicochemical stability of the protease and high yields of five biopharmaceutical proteins. This platform integrates affinity tagging with a modified caspase‐2 for in‐line cleavage, enabling streamlined downstream processing and consistent quality across diverse targets. Foundational work on high‐throughput expression in E. coli has charted the path towards parallelised cloning, expression and purification pipelines, highlighting advances in mRNA secondary‐structure prediction, automated liquid handling and fusion‐tag libraries to accelerate functional screening of hundreds of proteins. Seminal strategies for disulfide bond‐dependent proteins have illuminated the exploitation of periplasmic secretion pathways, engineered oxidising cytoplasmic strains and co‐expressed isomerases to achieve correct folding of complex, bond‐rich polypeptides. Collectively, these developments underscore a coherent trajectory from molecular design to scalable biomanufacturing, with an emphasis on modularity, yield and the retention of native functionality.

Recombinant Protein Expression in Bacterial Systems publication trend

The graph below shows the total number of articles in recombinant protein expression in bacterial systems across all publications each year (not limited to Nature Index journals).

Technical terms

Codon optimisation: Adjustment of a gene’s codon usage to match the tRNA abundance of the host for improved translation efficiency.

Fusion tag: A peptide or protein domain genetically linked to the target to enhance solubility or enable affinity purification.

Inducible promoter: A regulatory DNA sequence that permits controlled initiation of transcription upon addition of a specific inducer molecule.

Inclusion bodies: Dense, insoluble aggregates of overexpressed proteins in the bacterial cytoplasm, often requiring solubilisation and refolding.

Periplasm: The oxidising compartment between inner and outer membranes of Gram‐negative bacteria, favourable for disulfide bond formation.

References

1. Recombinant protein expression in Escherichia coli: advances and challenges. Frontiers in Microbiology (2014).
2. Fusion tags for protein solubility, purification and immunogenicity in Escherichia coli: the novel Fh8 system. Frontiers in Microbiology (2014).
3. Refolding Techniques for Recovering Biologically Active Recombinant Proteins from Inclusion Bodies. Biomolecules (2014).
4. Strategies for successful recombinant expression of disulfide bond-dependent proteins in Escherichia coli. Microbial Cell Factories (2009).
5. SHuffle, a novel Escherichia coli protein expression strain capable of correctly folding disulfide bonded proteins in its cytoplasm. Microbial Cell Factories (2012).
6. Scar-free tag removal by CASPON® enzyme with broad physicochemical stability in biomanufacturing – A case study of five proteins. Separation and Purification Technology (2025).
7. High-throughput recombinant protein expression in Escherichia coli: current status and future perspectives. Open Biology (2016).