Pichia pastoris: A notable heterologous expression system for the production of foreign proteins—Vaccines

175-186Improvements in yeast expression systems, coupled with the development of more information on methylotrophic yeast are expanding the role of yeast in the process of understanding and engineering eukaryotic proteins. Pichia pastoris has become a highly popular expression host for the production of a wide variety of intracellular and extracellular recombinant proteins of interest. Initial success with this system was greatly facilitated by the development of versatile expression vectors that were almost exclusively based on the strong, tightly regulated promoter of the P. pastoris major alcohol oxidase gene. Recent advances in the development of yeast as a host for the production of heterologous proteins have provided a catalogue of new applications, methods and system components, which will help us to understand about more details and applications of the system even further. Characteristic features of Pichia species, which are the most advantageous and favourable, have resulted in an increasing number of biotechnological applications. During the past two decades, P. pastoris has been developed into a highly successful system, due to its increasing popularity, which can be attributed to several factors such as, the simplicity of techniques needed for the molecular genetic manipulation; the ability to produce foreign proteins at high level, the capability of performing many eukaryotic post-translational modifications (glycosylation, disulfide bond formation and proteolytic processing) and finally the availability of the expression system as a commercially available kit