Studies on the Growth of Chlorella by Continuous Cultivation

Abstract

Equations which indicate the yield and the growth rate or flow rate at the condition that some transparent light is present, were introduced. From these equations and experimental yields, the extinction coefficient of cell suspension for compound light was calculated. It was found that if Beer's law is applicable to cell suspension, it is applicable with the changing value of the extinction coefficient through the suspension in case of compound light, from 0.42 to 0.26 for instace, because of the selective absorption of compound light by the suspension. The coefficient also changes with the change of light intensity, because the light of high in-tensity produces cells of low chlorophyll content, especially at a low cell concentration. And so, at a low light intensity, the yield is determined by the high value of the coefficient at a low population density and by the low value at a high population density, while, at a high light intensity, it is determined by the low value of the coefficient at both low and high population densities. Finally, a brief consideration on mass culture of Chlorella was presented, the merits and demerits of applying the continuous culture system and the multi-vessel system in continuous culture to mass culture being discussed.