Yeast Expression System for Vaccine Production
Expressing proteins in yeast often act as an alternative to bacterial expression system for vaccine production with both high yield and additional benefits of post-translational modifications as well as secretory expression.
Comparison of Expression systems
| Characteristics | E. coli | Yeast | Insect cells | Mammalian cells |
|---|---|---|---|---|
| Growth speed | rapid (30 min) | rapid (90 min) | slow (18-24 h) | slow (24 h) |
| Expense of growth medium | low | low | high | high |
| Expression level | high | low-high | low-high | low-moderate |
| Secretory expression | secretion to periplasm | secretion to medium | secretion to medium | secretion to medium |
| Posttranslational modification | ||||
| Protein folding | refolding required | refolding sometimes required | suitable folding | suitable folding |
| N-linked glycosulation | none | high mannose | simple | complex |
| Gamma-Carboxylation | no | no | no | yes |
| Phosphorylation | no | yes | yes | yes |
| Acetylation | no | yes | yes | yes |
| Acylation | no | yes | yes | yes |
| O-linked glycosulation | no | yes | yes | yes |
At present, there are many expression systems in the world that can produce protein of interest. Each expression system has its own advantages. Although the principles and methods of operation of different expression systems vary widely, the process of obtaining target proteins for subsequent research is basically the same. The general flow of a protein production includes gene expression, posttranslational modifications, protein secretion and downstream processing, each of steps requiring detailed design. Creative Biolabs possess various yeast expression systems and diversified flexible strategies to meet your sundry requirements for protein production.
Saccharomyces cerevisiae Expression System
Saccharomyces cerevisiae is a species of yeast which is widely applied in winemaking, baking and brewing. The species is generally found on skins of grapes and other ripe fruits. Defined as a most studied eukaryotic model organism for protein production, S. cerevisiae has its own superiority to bacteria in posttranslational modifications and secretion, relieving the burden of purification and modification significantly. Besides, S. cerevisiae is easy to culture in low pH conditions as well as high sugar and ethanol concentrations, even could tolerate high osmotic pressure, all of which enable the species a desired tool for industrial fermentation.
Kluyveromyces lactis Expression System
Kluyveromyces lactis (the former Saccharomyces lactis) is a yeast of ability to assimilate lactose and transform it into lactic acid. After decades of research, the organism has been widely used in food industry due to its well-established merit of safety. After a transformation system was built in 1980s, K. lactis started to be applied for protein production as an expression host.
As an expression system, K. lactis has following advantages over other yeast, including:
- Inexpensive culture conditions containing lactose
- Well-developed genetics
- High yield of product up to g/l scale
- GRAS status
- Secretory expression of high molecular weight proteins
Pichia pastoris Expression System
Pichia pastoris, a kind of methylotrophic yeast, is one of the most popular tools to generate recombinant protein with a success of large-scale productivity. P. pastoris was used to convert methanol into protein source for animal feed in the past, but today, it has been engineered to research cell biology as a model eukaryote and to produce recombinant protein. As a highly accepted system for protein expression, P. pastoris has its distinguished traits in following aspects:
- Ability to grow to high cell densities
- Robust inducible promoters
- Ease of manipulation
- Extra process to stabilize product
- High production output
- Secretory protein production
- Requirements for precise fermentation conditions
- Capable of multiple posttranslational modification
- Demands of MetOH induction (necessary for explosive-safe fermentors)
Hansenula polymorpha Expression System
Hansenula polymorpha is one of the four methylotrophic yeasts, the other three species are Candida boidinii, Pichia methanolica, and Pichia pastoris. Along with Pichia pastoris, Hansenula polymorpha is of extensively application in protein expression. As H. polymorpha is much more thermostable than P. pastoris, thus having a potential in producing proteins studied for crystallology. The main features of H. polymorpha expression system are listed below:
- Secretes proteins on certain conditions
- Short fermentation times
- High level expression and simple purification
- Rarely hyper-glycosylation of the protein product
- Thermotolerant
- Capacity of high-copy integration
- Free of toxins and viral contaminations.
Our Platforms of Yeast Expression System
- Codon optimization and gene synthesis
- A variety of well-established yeast strains and expressing vectors
- Expression evaluation and optimization
- Large-scale protein expression and subsequent processing
- Process development and improvement
Creative Biolabs is a leader in the field of vaccine development and has extensive experiences in protein expressing for decades. We are furnished with a professional team expertized in protein production, aiming at providing you with the most complete service. If any interests you have in our services, please do not be hesitate to contact us for more details.
All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.
