Driving improvements from Discovery to Approval

Pseudomonas fluorescens based protein production for recombinant proteins.


Up to 10-20x higher yield than traditional expression platforms, including yeast, E. coli and CHO.


80%+ success expressing proteins that have failed other systems.

A Better Organism
Metabolically diverse with higher inherent recombinant protein production efficiency.

Built for Efficiency
High cell densities, short fermentations (~48h), fully animal/antibiotic-free. 

Scalable and Stable
From 0.5 mL to >150 kL, in glass, stainless, and disposable systems.

Automated HTP Platform
Identifies optimal production strains in 2 to 14 weeks.

How It Works

Our industry-proven Pfenex Expression Technology® platform starts with an automated, high-throughput, rapid candidate selection process that combines over 30 years of know-how in expressing challenging molecules. Unlike CHO and E. coli which have their roots as research tools, the Pfenex platform is based on Pseudomonas fluorescens and was specifically designed as an expression platform for producing large quantities of high quality, complex proteins at low cost.  

With more than 100 worldwide collaborations and five product approvals powered by the Pfenex platform over the last twenty years, our institutional knowledge and unmatched capabilities have achieved protein titers and production costs that were previously unattainable. 


Our team possesses extensive CMC experience and knowledge gained from developing both internal and partnered products. Our comprehensive approach and expertise mitigate risks associated with critical manufacturing and regulatory milestones. Unlike other expression platform developers, we are among the few who have successfully advanced products from concept to approval with our technology. 


Our Pfenex Expression Technology platform has demonstrated its versatility through the production and commercialization of a broad range of natural and engineered proteins across a multitude of classes.




Protein/Peptide/Library Candidates


Years of Expression

Collaborations & Partners


We currently work with a multitude of organizations across a variety of programs. From advanced expression host engineering through the development of custom RNA and DNA polymerases, we overcome development and production challenges to keep client programs on track. As a fully integrated CMC organization, we’re suited to ensure your success.

Arcellx, Inc. and Pfenex entered into a Development, Evaluation and License agreement in 2018 under which Arcellx gains access to the proprietary Pfenex Expression Technology platform to advance multiple proprietary sparX proteins that activate, silence and reprogram Antigen-Receptor Complex T-cell based therapies.

Teriparatide Injection, the first and only approved US-biosimilar to Eli Lilly’s Forteo®, was developed by Primrose Bio using the Pfenex Expression Technology® under the 505(b)(2) regulatory pathway. Launched in 2020, Teriparatide Injection was exclusively licensed to Alvogen in 2018 for further development and commercialization in the US, EU, and other regions.

In July 2021 Jazz launched Rylaze® (asparaginase erwinia chrysanthemi (recombinant)-rywn) using the Pfenex Expression Technology® platform. Using the Pfenex Expression Technology®, Rylaze went from DNA to FDA approval in less than six years and was approved as a component of a multi-agent chemotherapeutic regimen for the treatment of ALL or LBL in adult and pediatric patients one month or older who have developed hypersensitivity to E. coli-derived asparaginase. Jazz retains global rights to develop and market JZP341, a long-acting Erwinia asparaginase using the Pfenex Expression Technology for treating acute lymphoblastic leukemia and other hematological malignancies. 

Merck & Co., Inc., licensed our Pfenex Expression Technology to produce the CRM197 carrier protein for use in Merck conjugate vaccines. VAXNEUVANCE®, a 15-valent preventative Pneumococcal vaccine, uses CRM197 as its carrier protein and was approved in the US and EU in 2021. Additional Merck Pneumococcal vaccines under development include V116 and V117. 

Serum Institute of India Pvt. Ltd. (SIIPL) uses the Pfenex Expression Technology® to produce CRM197 for use in their conjugate vaccines, including Pneumosil® and MenFive®. SIIPL is Primrose Bio’s exclusive supplier of research and GMP grade CRM197, PeliCRM197®.

100+ partnerships in innovative protein and nucleic acid-based therapeutics.