Yeast Expression System

Yeast expression system is a common alternative antibody expression system to E. coli. It generally achieves the highest expression level in eukaryotic system including both secretion and intracellular expression. Yeast cells both have the advantages of producing proteins in microbes (high growth speed, easy genetic manipulation, high yield and low cost) and attribute of eukaryotic systems (post translational modifications, secretory expression). It is ideally suitable for large-scale production of recombinant eukaryotic proteins (including antibodies).

Creative Biolabs developed advanced YeastXceed™ system to generate antibodies with high yield possibility. We take into consideration of optimal copy plasmid backbones, yeast strains, inducibility, etc. and design the best methods for high-level antibody production.

Two yeast strains, Saccharomyces cerevisiae and Picchia pastoris, are available for protein expression.

Saccharomyces cerevisiae yeast expression system

S. cerevisiae was an obvious first choice for high-yielding, animal-free protein production as we have broad knowledge of its genetic information and extensive experience in industrial use. A Saccharomyces cerevisiae-based expression system provides the perfect vehicle for stable, high-yielding secretion of scFv antibody fragments. The promoters used in S. cerevisiae are commonly yeast alcohol dehydrogenase 1 (ADH1) gene and glyceraldehyde-3'-dehydrogenase (GAPDH) gene.

Creative Biolabs' engineering-enhanced protein expression technologies enable a high success rate of antibodies. Antibodies as inactive inclusion bodies can be produced successfully by our yeast expression system using native or yeast secretion signals.

Picchia pastoris yeast expression system

Using S. cerevisiae as the expression host has some general limitations:

• The promoters typically used (e.g. GAPDH promoter) were derived from genes of the glycolytic pathway and enabled constitutive expression. A constitutive expression mode exerts negative selection pressure on cells during fermentation because of product accumulation.
• Plasmid loss occurs even in selective medium, resulting in instability of expression strains and product yield.

These limitations and the quest for higher yields prompted the search for alternative yeasts and filamentous fungi as novel expression hosts for protein production. Creative Biolabs has developed Pichia pastoris-based expression system for high yield antibody expression. The fermentation process for the methylotrophic yeasts is dependent on efficient methanol induction. The P. pastoris system ensures high-quality antibody production to meet all your requirements.

Creative Biolabs' HostOptim™ technology is used to increase translation rates by increasing the protein per mRNA ratio. HostOptim™ can be combined with transcription enhancing or other production improving technologies to increase initial expression levels largely.

Yeast expression technology's benefits

• Ease of use similar to E. coli.
• Some post-translational modification.
• The use of budding yeast S. cerevisiae in the production of bread and alcoholic beverages may result in a high level of confidence in the safety of the organism.

For Research Use Only.