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Analytical characterization of proteins is a critical task for developing therapeutics and subunit vaccine candidates. Assessing candidates with a battery of biophysical assays can inform the selection of one that exhibits properties consistent with a given target product profile (TPP). Such assessments, however, require several milligrams of purified protein, and ideal assessments of the physicochemical attributes of the proteins should not include unnatural modifications like peptide tags for purification. Here, we describe a fast two‐stage minimal purification process for recombinant proteins secreted by the yeast host Komagataella phaffii from a 20 mL culture supernatant. This method comprises a buffer exchange and filtration with a Q‐membrane filter and we demonstrate sufficient removal of key supernatant impurities including host‐cell proteins (HCPs) and DNA with yields of 1–2 mg and >60% purity. This degree of purity enables characterizing the resulting proteins using affinity binding, mass spectrometry, and differential scanning calorimetry. We first evaluated this method to purify an engineered SARS‐CoV‐2 subunit protein antigen and compared the purified protein to a conventional two‐step chromatographic process. We then applied this method to compare several SARS‐CoV‐2 RBD sequences. Finally, we show this simple process can be applied to a range of other proteins, including a single‐domain antibody, a rotavirus protein subunit, and a human growth hormone. This simple and fast developability methodology obviates the need for genetic tagging or full chromatographic development when assessing and comparing early‐stage protein therapeutics and vaccine candidates produced in K. phaffii. [ABSTRACT FROM AUTHOR]

Prevention of COVID‐19 on a global scale will require the continued development of high‐volume, low‐cost platforms for the manufacturing of vaccines to supply ongoing demand. Vaccine candidates based on recombinant protein subunits remain important because they can be manufactured at low costs in existing large‐scale production facilities that use microbial hosts like Komagataella phaffii (Pichia pastoris). Here, we report an improved and scalable manufacturing approach for the SARS‐CoV‐2 spike protein receptor‐binding domain (RBD); this protein is a key antigen for several reported vaccine candidates. We genetically engineered a manufacturing strain of K. phaffii to obviate the requirement for methanol induction of the recombinant gene. Methanol‐free production improved the secreted titer of the RBD protein by >5X by alleviating protein folding stress. Removal of methanol from the production process enabled to scale up to a 1200 L pre‐existing production facility. This engineered strain is now used to produce an RBD‐based vaccine antigen that is currently in clinical trials and could be used to produce other variants of RBD as needed for future vaccines. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) are a major class of biopharmaceuticals manufactured by well-established processes using Chinese Hamster Ovary (CHO) cells. Next-generation biomanufacturing using alternative hosts like Komagataella phaffii could improve the accessibility of these medicines, address broad societal goals for sustainability, and offer financial advantages for accelerated development of new products. Antibodies produced by K. phaffii, however, may manifest unique molecular quality attributes, like host-dependent, product-related variants, that could raise potential concerns for clinical use. We demonstrate here conservative modifications to the amino acid sequence of aglycosylated antibodies based on the human IgG1 isotype that minimize product-related variations when secreted by K. phaffii. A combination of 2-3 changes of amino acids reduced variations across six different aglycosylated versions of commercial mAbs. Expression of a modified sequence of NIST mAb in both K. phaffii and CHO cells showed comparable biophysical properties and molecular variations. These results suggest a path toward the production of high-quality mAbs that could be expressed interchangeably by either yeast or mammalian cells. Improving molecular designs of proteins to enable a range of manufacturing strategies for well-characterized biopharmaceuticals could accelerate global accessibility and innovations., (© 2024 The Author(s). Biotechnology and Bioengineering published by Wiley Periodicals LLC.)