Recombinant therapeutic proteins and many vaccines are costly to manufacture. Current state-of-the-art protein expression systems include: * Mammalian Chinese Hamster Ovary (CHO) and HEK293 systems. _Limitations:_ Slow-growing cells, expensive media, high energy burden (e.g., for supplying CO2, and for heating the cell cultures), high environmental burden with disposable technologies, and less amenable to large-volume manufacture. * Lonza's XS _E. coli_ system. _Limitations:_ Inability to form disulphide bonds causes misfolded proteins to aggregate as insoluble inclusion bodies that are not secreted, requiring cell lysis and further processing to generate functional proteins. * Validogen's _Pichia pastoris_ system. _Limitations:_ Transformations require toxic zeomycin; integrated-plasmids hamper strain development; complex IP/licensing issues; glycated lysine residues can cause loss-of-function and unwanted immunogenicity; methanol/oxygen feeds pose a fire risk at scale. Few _Pichia_-derived products have received FDA or MHRA approval. Baker's yeast (_Saccharomyces cerevisiae_) has a long, safe track-record of FDA approve biologics and is generally regarded as safe (GRAS), e.g., insulins, and has natural adaptability industrial-scale conditions whilst correctly producing biologically active eukaryotic proteins. Despite this, no 'open' commercial expression systems are available. Baker's yeast systems are typically developed for in-house use only. Yields are frequently sub-optimal; development times are slow, and strains are not easily adapted to new products. There is an opportunity to optimise and commercialise the next-generation _S. cerevisiae_ protein expression platform for a broader therapeutics market. Phenotypeca are developing the _S. cerevisiae_-based platform 'PhenoDev' for high-yield expression of recombinant proteins to address this unmet need. To realise the full market potential, PhenoDev must be optimised for protein secretion by solving protease and protein folding issues these therapeutics require. The improved PhenoDev platform will be validated by another UK SME, Isogenica, who will benefit from an alternative to _E. coli_ for developing and producing VHH antibodies they want to sell.

Phenotypeca Ltd is a biotechnology company based in the University of Nottingham's Synthetic Biology Research Centre developing next-generation yeast for the manufacture of recombinant proteins, such as biopharmaceuticals. Using a genetically diverse collection of natural baker's yeast engineered for large-scale industrial processes we breed up to a billion progeny and select cells optimised for the product and process of choice. Baker's yeast has been safely used for over 30‑years for the bulk manufacture of biologics, such as insulin and vaccines, and is relatively inexpensive compared to mammalian systems. This project aims to address an urgent unmet need for SARS-CoV-2 viral antigens for the UK's production of serological assays, used to identify individuals with immunity to COVID-19\. Phenotypeca will produce yeast strains for the manufacture of specific antigens for evaluation by Oxford University's Jenner Institute, and build UK partnerships for their supply to serological assay producers. Parts of the SARS-CoV-2 virion have strong homology to other coronaviruses, making it challenging to produce tests that are both specific (no false positives, risking COVID-19 spreading) and sensitive (no false negatives, preventing people with immunity from returning to normal activities). To achieve this, we have designed multiple antigens from unique parts of the virus particle's structural proteins, including an exposed region known to bind the human ACE2 receptor, which has been guided by previous work that successfully made high-quality antigens from yeast after the 2003 coronavirus outbreak. We aim to develop yeast strains for the secretion of these antigens to simplify purification and manufacture.

Recombinant protein expression is the keystone manufacturing technique supporting production of many biological therapies. A large number of protein expression systems exist, but the majority of biological drugs and protein products that are approved for clinical use have been manufactured using mammalian cell culture techniques. These manufacturing processes are laborious, slow, and expensive. Yeast systems offer a significantly simpler way of expressing recombinant proteins at scale compared to mammalian cell culture, and at a greatly reduced cost. A number of yeast protein expression systems have been commercialised. However, the baker's yeast (Saccharomyces cerevisiae) expression systems, which are most commonly used in industry for biologics production, have never themselves been widely commercialised by the companies that developed them. The patent protection for these baker's yeast systems has now expired or is expiring. This engenders considerable freedom to create new systems and develop new IP surrounding enhanced, second-generation protein expression systems utilising S. cerevisiae as their protein-production powerhouse and making this technology widely available to new companies wishing to bring recombinant products to the market. The project will enable Phenotypeca to develop novel strains of S. cerevisiae to be created that can be quickly and easily tailored to optimize production of recombinant proteins. In this instance, the platform will be exemplified by producing a protein (H-Guard) for another UK SME - Invizius - which is a coating used on dialysis equipment to prevent inflammatory responses induced by repeated exposure to dialyser membranes. Invizius will work alongside the Centre for Process Innovation (CPI), who join the consortium as grant funded partners to conduct industrial fermentation modelling to identify the most suitable for scale-up production. The project supports Phenotypeca to become a service provider for clients wanting S. cerevisiae-based protein expression systems. There are currently no commercial providers of industrial S. cerevisiae systems -- all S. cerevisiae systems used industrially are proprietary systems developed in-house by other companies who don't want to share their technology of offer a development service. Phenotypeca is attempting to overcome the unmet market need for S. cerevisiae protein expression systems, especially for a class of therapeutic peptides for which Pichia pastoris-based yeast systems cannot meet the quality and regulatory requirements.