Screening and Selection of Production Strains: Secretory Protein Expression and Analysis in Hansenula polymorpha.

The thermotolerant methylotrophic yeast Hansenula polymorpha has been used as a host for the high-level production of recombinant proteins from industrial enzymes to therapeutic proteins. Despite favorable characteristics of the H. polymorpha-based platform for application to heterologous gene expression, several problems and limitations, such as over-glycosylation and proteolytic degradation, can be encountered in the development of production strains for secretory proteins. Here, H. polymorpha genetic tools and host strains, developed for authentic processing and modification of secretory recombinant proteins, are introduced with the analytical protocols.