Introduction to Pichia pastoris

Abstract

Pichia pastoris has become a highly successful system for the expression of heterologous genes. Several factors have contributed to its rapid acceptance, the most important of which include: 1. A promoter derived from the alcohol oxidase I (AOX1) gene of P. pastoris that is uniquely suited for the controlled expression of foreign genes; 2. The similarity of techniques needed for the molecular genetic manipulation of P. pastoris to those of Saccharomyces cerevisiae, one of the most well-characterized experimental systems in modern biology; 3. The strong preference of P. pastoris for respiratory growth, a key physiological trait that greatly facilitates its culturing at high cell densities relative to fermentative yeasts; and 4. A 1993 decision by Phillips Petroleum Company (continued by Research Corporation Technologies [RTC]) to release the P. pastoris expression system to academic research laboratories, the consequence of which has been an explosion in the knowledge base of the system (Fig. 1).