The 4th Hansenula polymorpha Worldwide Network Conference, Haren (The Netherlands), 3–5 September 2006

Abstract

The Hansenula polymorpha worldwide network conference is organized every other year and aims to bring together scientists from academia and industry. The participating groups utilize the thermotolerant methylotrophic yeast H. polymorpha (syn. Pichia angusta ) during their studies. This organism is a well-known model organism for specific fundamental studies, for example on methanol and nitrate metabolism and peroxisome homeostasis. In addition, H. polymorpha has become a powerful production platform for heterologous protein production, which is reflected in the fact that usually half of the participants of these meetings come from biotechnological companies. After meetings in Dusseldorf, Germany (2000), La Laguna, Tenerife, Spain (2002) and Ancona, Sicily, Italy (2004), the 4th Hansenula polymorpha Worldwide Network Conference was organized by the laboratory of one of its founders, Marten Veenhuis (University of Groningen, Haren, the Netherlands). The conference started with a detailed overview by Thomas Egli (Swiss Federal Institute of Aquatic Science and Technology, Dubendorf, Switzerland) on some remarkable characteristics of methylotrophic yeasts when fed with mixed substrates. Although in the laboratory H. polymorpha is mostly cultured on one specific carbon and nitrogen source, in most natural environments microorganisms face a wide range of nutrients. Detailed analyses have clearly demonstrated that methylotrophic yeast simultaneously utilizing glucose and methanol as carbon sources display a number of characteristic properties including (1) improved stability of the culture towards sudden changes in the environment, (2) enhanced growth rates, and (3) improved productivity of commercially interesting enzymes. ### Peroxisome homeostasis Peroxisomes are single-membrane-bound organelles present in all eukaryotes. Although peroxisomes harbour a wide range of metabolic functions, peroxisome biogenesis and proliferation seem to be conserved throughout evolution. To date, more than 30 genes ( PEX genes) involved in these pathways have been identified. Jan Kiel (University of Groningen, Haren, the Netherlands) presented a comparison of PEX genes in fungal genomes and in the …