Pichia pastoris yeast: an appropriate experimental tool for recombinant proteins production

The bacterial expression system has the ability to produce high amounts of recombinant proteins, but the produced proteins might not have suitable structure folding and post-translational modifications. In the other hand, the mammalian cell expression system also provides the suitable form for protein production; however the higher costs and generally low production yielding for this expression system made the researchers to have tendency to study on the yeast expression system. Yeasts are particularly suited to expression of foreign proteins for numerous features, including easy genetic manipulation, high levels of intracellularly or extracellularly protein expression, and the ability to carry out higher eukaryotic protein modifications. The methylotrophic yeast Pichia pastoris has been developed for the production of various recombinant proteins and growth into high cell densities in an inexpensive medium. Secretion of low amounts of yeast endogenous proteins in cell culture media makes the simple purification of expressed recombinant proteins. However, the Pichia pastoris Glyco-switch strains with the ability to produce eukaryotic glycoproteins with the same post-translational modifications fixed the only deficiency in yeast expression system. Accordingly, Pichia pastoris is an appropriate secretory system for obtaining larger quantities of correct products, in compare to other host cells.