The tumbling reactor: a new reactor design for biotechnology - Cultivation of the phototrophic micro-alga Scenedesmus communis

A new system for the growth of mammalian cells was developed and its biotechnological suitability was proven by the sterile cultivation of the phototrophic micro-alga Scenedesmus communis, as an easy to cultivate model organism. For this purpose, the bioreactor was combined with a newly developed equipment for irradiation of large scale cultures of phototrophic micro-organisms. Cultivation was performed in a 40 liter scale at 25 degrees C and a pH of 6.0 to 6.5. The aeration gas consisted of 2% or 7% of CO2 in N-2. The aeration rate was V-gas = 19.6 L.h(-1), the stirring speed was n = 70 or 56 min(-1). The new reactor consists of 8 totally immersed fluorescent tubes located around a cylinder for bubble free aeration which is moving within the cultivation broth. Results of the cultivation reveal the suitability of this newly designed system for biotechnological use and its high scale-up potential.