Mass cultivation of algae in pure heavy water

Strains of the green algae Scenedesmus obliquus, Chlorella vulgaris , and C. pyrenoidosa 7‐11‐05, and of the blue‐green algae Fremyella diplosiphon, Plectonema calothricoides, Phormidium luridum , and Synechococcus lividus have been mass cultured autotrophically in essentially pure D 2 O. Closed Lucite rocking‐box units containing 5 liters of culture media can produce 1 to 2 g. (dry weight) per day of fully deuteriated algae or of fully deuteriated, fully 15 N‐substituted algae. Racks for six such culture units are readily constructed from commerically available parts. Operation has been routine and essentially trouble‐free. The algae produced have proved to be an excellent source of completely isotopically substituted metabolites.