Hansenula polymorpha (Pichia angusta)

Abstract

A small and closely related group of yeasts is capable of using methanol as sole source of carbon and energy. Among these methylotrophic organisms, Hansenula polymorpha in particular has gained increasing attention in recent years, in both basic and applied sciences. This is mainly due to two physiological features that are an integral part of the methanol-utilizing machinery of this yeast. One is the expression of huge amounts of the key methanol-metabolizing enzymes, which can, in the case of the methanol oxidase, amount to up to one third of the total cellular protein. The expression is driven by very strong promoters that form the basis for a highly competitive system to produce foreign proteins at industrial scale (Gellissen et al. 1994). The other prominent characteristic of H. polymorpha is that the expression is accompanied by a dramatic growth and proliferation of microbodies, i.e., peroxisomes (Veenhuis and Harder 1987). H. polymorpha thus served and, in addition to the recent introduction of other systems such as Saccharomyces cerevisiae, still continues to serve as a valuable model organism to study the biogenesis of these organelles. Although we will briefly discuss the contributions of H. polymorpha to the field of peroxisome research, our main focus within this chapter belongs to the practical aspects that are of importance in working with this yeast.