a slowly rotating, nearly horizontal metallic shaft. Onto these clips, glass containersof 3 cm diameter closed on both sides (about 70 ml volume) are fixed, to which15 ml liquid medium is applied. For gas exchange, an opening of about 1.5 cm witha collar of about 1.5 cm is maintained. The shaft rotates at 1 rpm, resulting in thenutrient medium being continuously mixed and aerated. Due to the development of