Pichia pastoris | |
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Scientific classification | |
Kingdom: | Fungi |
Phylum: | Ascomycota |
Class: | Saccharomycetes |
Order: | Saccharomycetales |
Family: | Saccharomycetaceae |
Genus: | Komagataella |
Species: | P. pastoris |
Binomial name | |
Pichia pastoris (Guillierm.) Phaff 1956 |
Pichia pastoris is a species of methylotrophic yeast. Pichia is widely used for protein production using recombinant DNA techniques. Hence it is used in biochemical and genetic research in academia and the biotechnical industry.
Pichia pastoris is frequently used as an expression system for the production of proteins. A number of properties makes P. pastoris suited for this task: P. pastoris has a high growth rate and is able to grow on a simple, inexpensive medium. P. pastoris can grow in either shake flasks or a fermenter, which makes it suitable for both small and large scale production.
Pichia pastoris has two alcohol oxidase genes, Aox1 and Aox2, which have a strongly inducible promoter. These genes allow Pichia to use methanol as a carbon and energy source. The AOX promoters are induced by methanol and are repressed by e.g. glucose. Usually the gene for the desired protein is introduced under the control of the AOX1 promoter, which means that protein production can be induced by the addition of methanol. In a popular expression vector, the desired protein is produced as a fusion product to the secretion signal of the α-mating factor from Saccharomyces cerevisiae (baker's yeast). This causes the protein to be secreted into the growth medium, which greatly facilitates subsequent protein purification. There are commercially available plasmids that have these features incorporated (such as the pPICZα vector).