Genetics and molecular physiology of the yeast Kluyveromyces lactis.

With the recent development of powerful molecular genetic tools, Kluyveromyces lactis has become an excellent alternative yeast model organism for studying the relationships between genetics and physiology. In particular, comparative yeast research has been providing insights into the strikingly different physiological strategies that are reflected by dominance of respiration over fermentation in K. lactis versus Saccharomyces cerevisiae. Other than S. cerevisiae, whose physiology is exceptionally affected by the so-called glucose effect, K. lactis is adapted to aerobiosis and its respiratory system does not underlie glucose repression. As a consequence, K. lactis has been successfully established in biomass-directed industrial applications and large-scale expression of biotechnically relevant gene products. In addition, K. lactis maintains species-specific phenomena such as the "DNA-killer system, " analyses of which are promising to extend our knowledge about microbial competition and the fundamentals of plasmid biology.