Over the last decades molecular biologic techniques have been developed to alter
the genome and proteome of Tetrahymena thermophila thereby providing the basis for recombinant
protein expression including functional human enzymes. The biotechnological potential of
Tetrahymena has been proved in numerous publications, demonstrating fast growth, high biomass,
fermentation in ordinary bacterial/yeast equipment, up-scalability, existence of cheap and chemical
defined media. For these reasons Tetrahymena offers promising opportunities for the development
of a high expression system. Yet optimised high yield strains with protease deficiency such as
commonly used in yeast and bacterial systems are not available.