The methylotrophic yeasts Hansenula polymorpha and Pichia pastoris : favourable cell factories in various applications

The methylotrophic yeasts Hansenula polymorpha and Pichia pastoris are extensively used as model organisms in studies on peroxisome biogenesis and degradation. In addition, these yeasts have gained increasing interest as cell factories in various production processes. In this contribution, an overview is presented on several aspects of the application of both cell factories. Both yeast species have been successfully applied for the production of heterologous products. The molecular tools are highly developed, e.g. the availability of a large variety of expression vectors in which various constitutive and inducible promoters are available to control protein production. The use of both methylotrophs offers a specific advantage to accumulate foreign proteins inside peroxisomes. This is in particular advantageous when the produced protein is toxic for the yeast cell or when undesired modifications (e.g. proteolysis or glycosylation) have to be prevented. Furthermore, H. polymorpha might be the organism of choice for the production of gel-forming proteins as well as heterologous (including human) membrane proteins