Redefining recombinant protein production to accelerate biopharmaceutical development

  1. 22nd Apr, 2024

Recombinant protein production is an important technique for generating large quantities of proteins in a variety of pharmaceutical, agricultural and industrial applications. It is widely used in the development and manufacture of drugs – such as insulin, growth factors and monoclonal antibodies –vaccines and enzymes. The method is also used within agriculture to develop more sustainable and resilient crops with improved characteristics, such as disease and pest resistance, enhanced nutritional content and higher yields. These features will be crucial in feeding the world’s growing population in the future, while safeguarding the health of the natural environment.

Addressing challenges in recombinant protein production 

Despite a wide interest in recombinant protein production, there are still several hurdles to consider when choosing this technique.Some recombinant proteins require complex post-translational modifications such as glycosylation for correct expression and activity in their native form, and this is why mammalian cell expression systems, like Chinese hamster ovary (CHO) cells, are often the first choice of host system. However, developing mammalian cell lines for recombinant protein production is a long and complex process requiring high levels of precision and expertise. These host organisms also require a media comprising of expensive components, exhibit slower cell growth and are highly sensitive to shear stresses. Scaling up recombinant protein production with mammalian cell lines can therefore be time consuming and expensive for manufacturers.1

Escherichia coli (E. coli) is a well-established alternative to mammalian cell lines, and – thanks to the many molecular tools and protocols developed over the years2 – has become the most popular microbial platform for recombinant expression of small molecules and proteins that do not require  complex post-translational modifications. Economically viable production of small molecules and other end products, such as fine chemicals, is also strongly dependent on compatibility of the target with the chosen biological system. Some recombinant proteins or small molecules – such as antimicrobial peptides – may prove toxic to the selected host, leading to genetic rearrangements, target degradation and overall poor yields.2,3 On top of this, impurities like native proteins, DNA, RNA metabolites, truncated forms and endotoxins can compromise biomedical applications4–6 and can be difficult to remove during processing without adversely affecting yield of the target molecule. These complications mean that it can be challenging  to identify, develop and optimise a scalable downstream process that effectively purifies a protein and allows its clinical progression. 

Advancing medicine and sustainability with microbial hosts 

There are several advantages to performing recombinant protein production in a microbial system instead of the more traditional mammalian cells. E. coli is often considered the go-to alternative host, but each microbial species possesses its own strengths that render it ideal for expressing certain proteins. Microbial hosts replicate quickly with high growth densities, and require simpler, less expensive growth media than mammalian cells. For example, Pichia pastoris (P. pastoris) is a widely  used host organism for recombinant protein expression that secretes recombinant proteins into the extracellular environment,7 simplifying downstream purification processes and decreasing the cost of manufacturing. It is also capable of introducing post-translation modifications such as glycosylation and disulfide bond formation, improving the solubility of secreted proteins and enhancing the efficacy and quality of biopharmaceutical products. In contrast to E. coli, P. pastoris does not produce endotoxins, making it a promising candidate host for the production of recombinant proteins.7 Engineered microbial P. pastoris strains combining the ability to perform post-translational modifications, rapid replication and high cell densities represent highly scalable recombinant protein expression systems that could significantly decrease the overall time to market and cost of a biotherapeutic target.8 Bacillus spp. also represent a viable alternative microbial host to mammalian cells when endotoxin-free secretion of recombinant protein is required. Ingenza has developed the proprietary gene design algorithm codABLE®, a library of secretion signals and protease-deficient strains – integral components of the inGenius® CMC suite – in order to boost expression, secretion and stability of the recombinant protein targets in Bacillus spp. 

Removing the roadblocks to drug discovery 

At Ingenza, we blend synthetic biology, genetic assembly and natural selection to create proprietary mammalian and microbial expression systems for the manufacture of high quality therapeutic and industrial recombinant protein products. Our modularity gives us the flexibility to tailor our engineering strategies and upstream and downstream processes to each customer’s needs, and we do not shy away from onboarding new host systems. Ingenza’s expert team will always find a way to express a target recombinant protein, regardless of the expression system used, and our zero per cent fail rate is a testament to this. It’s fair to say that our state-of-the-art approaches to recombinant protein production are helping to break down the hurdles that have previously hindered the development of novel solutions that will improve human health and support a more sustainable planet.

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  8. Pham J V., Yilma MA, Feliz A, et al. A Review of the Microbial Production of Bioactive Natural Products and Biologics. Front Microbiol. 2019;10. doi:10.3389/fmicb.2019.01404