Studies on the Mass Culture of <i>Phaeodactylum</i>

Abstract

Mass cultures of Phaeodactylum varying from 15 to 2,400 L have been successfully grown in covered tanks outside the laboratory. The maximum concentration obtained was 32,000 cells/mm 3 . Light has been shown to be a severely limiting factor in dense cultures. On the exponential phase of growth, under maximal light conditions, the highest division rate was 1 division in just under 24 hours. Addition of CO 2 has a markedly beneficial effect on maximum cell densities. Phosphate was taken up with extreme rapidity in dense mass cultures; repeated addition of N and P prolonged growth, provided CO 2 was added. A flagellate (Monas sp.) occurred regularly and became a predator in aging Phaeodactylum cultures. The monad multiplied only slowly in rapidly growing Phaeodactylum cultures. Some estimates are given of the dry weight of crop.