Expanding the applicability of bacterial fermentation for biomanufacturing could help significantly reduce the cost and time for manufacture of many important therapeutic peptides and proteins. Vectron Biosolutions is leading the charge in revolutionizing protein production with its advanced VB Secretion technology. By combining this innovation with its proprietary expression platform, VB Expression, Vectron has developed a platform capable of producing complex and valuable biomolecules in Escherichia coli and efficiently secreting them into the extracellular media — drastically simplifying downstream purification processes. Since its initial proof of concept, the company has achieved several key milestones, successfully producing a range of high-value therapeutic peptides and proteins. As Vectron collaborates with biopharma partners, it continues to push the boundaries of bacterial fermentation, moving steadily toward commercial readiness of this game-changing technology within the next two years.
Revolutionizing E. coli for Biomanufacturing: Unlocking the Power of Protein Secretion
E. coli is widely used for manufacturing certain therapeutic peptides and proteins due to its ability to deliver faster, more cost-effective production than cell culture–based solutions. However, one of the primary limitations of E. coli systems is that the expressed proteins are retained inside the cells, requiring extraction through cell lysis. This process introduces a range of cell-derived impurities that complicate downstream purification. Furthermore, many proteins tend to aggregate and form inclusion bodies (IBs) when produced intracellularly, which adds processing steps, increases costs, and often results in product loss.
The ability to engineer an E. coli system that can secrete proteins directly into the extracellular environment offers numerous advantages:
Simplified downstream processing: By reducing cell-derived impurities, secretion streamlines purification, cutting both costs and processing times.
Reduced cellular toxicity: Removing proteins from the cell decreases the risk of toxicity due to high expression levels, enabling greater overall productivity.
Minimized protein aggregation: Secretion lowers the concentration of proteins within the cell, reducing IB formation and the associated costs and time required for refolding processes.
Support for continuous processing: Secretion facilitates continuous processing methods like perfusion fermentation, which traditional E. coli systems cannot support due to their inability to export proteins.
These innovations expand the potential applications of E. coli fermentation for commercial-scale protein production, including proteins currently produced through more expensive methods or for emerging biotherapeutics. Beyond the biopharmaceutical industry, secretion technology has the potential to revolutionize protein production in sectors such as food, agriculture, and nutraceuticals, where cost-efficiency is especially critical. In these industries, profit margins are often smaller than in pharma, making low-cost manufacturing solutions like secretion-based systems particularly attractive. By reducing both upstream and downstream costs, secretion technology could enable companies in these fields to produce high-quality proteins more affordably, opening new possibilities for widespread, sustainable production.
VB Secretion Technology: Advancing Therapeutic Production in E. coli
In 2021, Vectron Biosolutions, building upon a portfolio of technologies created to optimize protein production in E coli, acquired a groundbreaking secretion technology from T3S Technologies. Originally developed by Professor Kelly Hughes and his team at the University of Utah, this system was designed for Salmonella, a bacterium currently undesired for pharmaceutical manufacturing. To overcome this limitation, Vectron adapted the platform for E. coli, a more established host for biopharmaceutical production, with the goal of enhancing protein secretion and broadening the use of bacterial fermentation in human therapeutic development.
Transitioning the technology from Salmonella to E. coli demanded significant engineering expertise. Extensive chromosomal modifications were necessary to enable efficient flagella-mediated secretion in E. coli, advancing Vectron’s platform as a robust solution for therapeutic protein production.
The controlled secretion technology utilizes engineered bacterial flagella — organelles that aid in bacterial cell movement — as highly specialized channels for protein secretion. This precise mechanism allows only the protein of interest to pass through the channel, ensuring controlled secretion directly into the surrounding media. Vectron’s VB Secretion Technology enables selective secretion of target proteins by attaching a tag recognized by the cell, ensuring that only the tagged protein passes through the secretion channels. While the intact, tagged proteins may be suitable for some uses, the removal of the tag is crucial for biotherapeutic applications due to immunogenicity concerns. Vectron is actively exploring various strategies for automated tag removal and anticipates selecting a primary method by the end of 2024. Further refinement will continue to optimize the chosen approach, as certain proteins may respond better to specific removal methods.
Key Milestones in VB Secretion Technology Development
Vectron Biosolutions achieved several key milestones in the development of its E. coli secretion platform. The first milestone was engineering new E. coli strains capable of synthesizing the appropriate flagella. Next, Vectron modified the host to improve the secretion efficiency. The third major milestone was achieving proof of concept by successfully detecting secreted proteins in the extracellular medium. The final milestone — a significant breakthrough — was the secretion of industrially valuable proteins.
Early studies at Vectron demonstrated the platform’s capacity to produce a variety of proteins, including beta-lactamase enzymes and therapeutic human growth hormone (hGH), using different engineered secretory E. coli strains. These studies achieved titers corresponding to excess of 100 mg/L in fed-batch processes. Subsequent generations of secretion strains have since shown improved secretion specificity and higher yields of a variety of other proteins.
Powered by VB Expression Technology
Today, Vectron’s VB Secretion Technology enables common industrial E. coli strains to synthesize flagella, which serve as channels for the directed transport of expressed proteins in a streamlined, one-step process. This system completely bypasses the periplasmic space, ensuring fast and efficient secretion. Each secretion channel can transport approximately 10,000 amino acids per second, a stark contrast to the Sec translocon, which translocates about 40 amino acids per second. Proteins are expressed using Vectron’s VB Expression technology, specifically designed to minimize the formation of IBs and generate soluble proteins — a critical requirement for successful secretion. By carefully controlling protein expression levels, Vectron maximizes yields of high-quality proteins, while fine-tuning the expression rate ensures proper protein folding.
Together, VB Expression and VB Secretion technologies form a highly complementary and advanced platform for bacterial fermentation. This integrated system allows for high-titer production of proteins with the right quality and quantity, efficiently secreted into the extracellular medium. The result is optimized upstream and downstream processes, reduced costs, and significantly shorter development timelines.
Significant Advances in Secretion Efficiency
Since achieving proof of concept for its VB Secretion technology, Vectron Biosolutions has demonstrated high-level secretion of many therapeutically valuable proteins and peptides, including GLP-1, insulin, GLP-2, somatotropin, glucagon, and others. Some of these examples are detailed in Table 1. Continued engineering of secretory E. coli strains has led to more versatile and scalable solutions, enabling ever higher titers with each new generation. Vectron’s ongoing R&D efforts focus on continuously enhancing the platform to support high-density, scalable production of therapeutically important proteins, improving both its flexibility and applicability for commercial manufacturing.
The proteins listed in Table 1 represent a range of peptides and proteins of varying sizes (up to 80 kilodaltons) and complexities. These results demonstrate the wide applicability of VB Secretion technology for producing both therapeutically and industrially relevant molecules, underscoring its versatility.
In parallel, Vectron has initiated the development of a sophisticated in silico model designed to predict the secretability of different proteins. While still in its early stages, this model has already proven useful for identifying many proteins and peptides that have been experimentally confirmed as efficiently secreted, helping refine the technology for broader use.
Table 1. Non-confidential proteins and peptides shown to be efficiently secreted with VB Secretion
Note: The molecules in Table 1 have successfully been secreted fused to our proprietary secretion tags. For many of these molecules, the secreted titers correspond to several grams per liter in fed-batch processes
Refining the Predictive Model for Protein Secretion
Proteins vary widely in their properties — such as size, hydrophobicity, and other structural factors — and as such it is expected that some will be secreted more efficiently than others. Vectron’s predictive model based on multivariate analysis was designed to evaluate a protein’s likelihood of successful secretion using VB Secretion technology, considering a range of parameters. While the model is not yet fully optimized, it has already proven effective in assessing therapeutic proteins currently on the market, offering insights into whether they are likely to be secreted.
As more experimental data on protein secretion is generated, it is fed back into the model, allowing for continuous improvement via machine learning. This iterative process will enhance the model’s accuracy over time, making it an increasingly reliable tool for predicting the secretability of a wide range of proteins.
Enabling Continuous Fermentation for Greater Efficiency
Perfusion cultivation, a specific type of continuous processing, has become increasingly popular for biologics production using cell culture. This approach offers numerous advantages by enabling the continuous harvesting of protein products, allowing for smaller production footprints and longer process durations to achieve the same product output. Moreover, it may deliver higher product quality and yields by maintaining a steady, optimal state that minimizes impurity generation. Unfortunately, these benefits have not been available for traditional E. coli fermentation processes, as the proteins expressed by the cells remain trapped inside, preventing continuous harvesting.
Vectron’s VB Expression and VB Secretion technologies aim to change that by facilitating high-performance perfusion fermentation. This approach eliminates the need for harvesting, lysing cells, and downstream purification after every upstream process cycle. Instead, the fermentation can continue for days or even weeks. This innovation not only lowers the cost of goods compared to batch fermentation but also reduces cellular toxicity and protein aggregation (including the formation of IBs) by avoiding high concentrations of over-expressed proteins. As a result, cell viability and productivity improve significantly.
To achieve this, Vectron is partnering with U.S.-based Scarab Genomics to engineer genetically stable E. coli strains optimized for perfusion fermentation. Early results by Scarab have shown protein production sustained for nearly 60 days — approximately 20 times longer than typical E. coli strains. By combining this breakthrough with VB Secretion technology, it is expected that perfusion fermentation processes could be extended over multiple weeks, offering tremendous value for therapeutic protein production.
Building Success Together: Vectron’s Approach to Partnership
While challenges remain on the path to commercializing VB Secretion Technology, Vectron is making substantial progress in reshaping protein production through E. coli fermentation. The next steps in this journey are clearly mapped out, and confidence in achieving these goals is bolstered by the successes realized so far.
A significant portion of this progress is the result of close collaborations with customers. These partnerships have provided Vectron with additional data and practical insights that go beyond internal R&D, allowing for the fine-tuning of platform efficiency, yield optimization, and expanded application capabilities. Vectron is eager to continue working with new therapeutic protein developers to explore cost- and time-efficient fermentation-based manufacturing processes.
It is also worth noting that VB Expression and VB Secretion technologies are not limited to therapeutic protein production. These platforms can be applied across various industries, including food and beverage, nutraceuticals, and agriculture/feed. While Vectron primarily collaborates with biopharmaceutical companies, its technologies offer significant potential for reducing the cost of goods in a wide range of industrial protein production scenarios.
One Step Closer to Realizing E. coli 2.0
The advancements achieved so far with the VB Secretion technology — and the promising progress on the horizon — position Vectron Biosolutions to help the biopharmaceutical industry, and beyond, unlock the transformative potential of E. coli 2.0. This groundbreaking platform is poised to revolutionize protein production through bacterial fermentation, with broad applications across multiple industries.
As Vectron continues to push the boundaries of what E. coli can achieve, the technology is progressing well beyond proof-of-concept, evolving into a viable, cost-effective solution for commercial-scale production of diverse proteins. The journey is far from over, and with each step, Vectron draws closer to bringing this game-changing solution to market. We invite you to stay tuned as we continue to share updates, explore new partnerships, and reveal the next stages of this exciting endeavor.
