An Extension of the Theory of the Chemostat with Feedback of Organisms. Its Experimental Realization with a Yeast Culture

Homogeneous continuous-flow culture with some mechanical means for concentrating the biomass in the fermenter is termed a chemostat with feedback. The theory of the system has been reformulated and extended to include concentration of the biomass outside or inside the culture vessel by means such as centrifugation, filtration or gravity sedimentation. An import-ant feature of the general system is the provision of two effluents, one of con-centrated biomass and the other of diluted biomass. Experimentally, feedback was realized by filtration of one effluent stream. By this means, steady states were obtained over a wide range of flow rates; the values of biomass and growth-limiting substrate were in good agreement with the theory. The maxi-mum biomass output rate of the chemostat was increased fourfold