Improved Control of Organism Concentration in Continuous Cultures of Filamentous Micro-organisms

S ummary . Mycelium concentration and culture volume measurements in continuous cultures are affected by accretions of filamentous organisms at the overflow weir. A pinch valve is described which periodically closed the air and culture effluent tube. When released the outrush of air cleared the overflow system. With the device the standard deviations of the steady state mycelium dry weights were reduced to one third of their former value and progressive concentration of the organism was eliminated. Measurement of culture volume was corrected for gas retained in the mycelial mass.