Mild method of pre-concentration of Dunaliella salina from culture medium

The photo- and chemo-taxisms of Dunaliella salina were used to induce a cell concentration in a layer of fresh water pumped to the top of a saline culture through a circular diffuser. When two consecutive operations were imposed to a 2.2 m 2 raceway type algae pond, 90% of the biomass (at 0.7 dry cells/l) was recovered in 16% of the initial volume. The biomass, free from chemicals and/or mechanical damage, could be centrifuged to obtain a high quality biomass for human consumption. The remaining medium in the pond (containing the rest of the cells) could be re-innoculated and allow a new cycle of production.