The submerged or solid-state fermentation is used for the mass cultivation of microorganisms with the goal of either isolating the microorganisms themselves or the metabolic product or a microbial altered substrate (e.g. in the food-processing industry). Whereas nowadays submerged fermenters (fermenters with a liquid nutritive substrate) already are built with a capacity of up to 200.000 liters, it has still not yet been achieved to build solid state fermenters (fermenter with a solid nutritive substrate) with economically relevant volumes, that can be kept free of contaminations by foreign micro-organisms for longer periods and that allow an optimum in cultivation care at the same time.