The thesis focuses on the identification of important process parameters for an optimal cultivation of Leishmania tarentolae to prepare the biotechnological use of this expression system. The developed YE-medium, containing only hemin as substance of animal origin, could be used successfully for growth experiments, also under limiting glucose or hemin concentrations (chemostate). With the determined constants of the Monod model for glucose and hemin, the maximal specific growth and cell division rates and the yield coefficients for glucose and hemin, a basis is created for further designs of fermentation strategies and optimizations. The nutrient media and the developed bioprocess strategies support high cell densities (1.8x109 cells/ml; 14.5 g/l CDW) in combination with doubling times of 5 - 7 h. The investigations of this work occupy, that under the used experimental conditions the Monodmodel is in power for the growth of L. tarentolae, excluding glucose inhibition. Moreover, it was clearly pointed out, that the effects of substrates are greater than the influence of temperature or pH. This inaugurates good control possibilities for the specific growth rate or the specific cell division rate, respectively. Furthermore, it could be shown that the morphological changes of the cells enable a supplemental characterization of growth. Defined media could be developed with stabilizing substances for hemin. By addition of yeast-RNA, the cell density was nearly doubled (2.8 - 3.3x108 cells/ml maximal cell density) in the defined media. The earned knowledge’s from the wild type strain were transferred to the expression of three model proteins. Particularly with the expression of the glycoprotein hyaluronidase-1, the great potential of this new system could be demonstrated. The specific activity in the media supernatant was eight times higher than the reported one for insect cells [Hofinger et al. (2007)]. With the results of this work, prerequisites are made for using L. tarentolae for the production of recombinant proteins for diagnostic or therapeutic purposes. Because of the possibility for N-glycosylation of human proteins, L. tarentolae is an alternative expression system to mammalian cells.