In recent years, there has been an increasing focus on the methylotrophic yeast, Pichia pastoris, a host cell for the recombinant proteins expression. P. pastoris is easier to genetically manipulate and culture than mammalian cells, and high cell density cultivations can be easily achieved in the flasks or in the fermentors. P. pastoris is also a eukaryote, and thereby providesthe potential for producing soluble, correctly folded recombinant proteins that have undergone allthe post-translational modifications. The linearized foreign DNA can be inserted into its chromosomes via homologous recombination to generate stable cell lines. Furthermore, P. pastoris has strong AOX and GAP promoters to drive the recombinant expressions, therefore, production of high level target protein can be easily achieved. This article is to introduce the P. pastoris protein expression system.
