Continuous-dilution method for the mass culture of synchronized cells.

A new mass-culturing technique for synchronized cells is described. Continuous dilution with fresh culture medium provides the cells with nearly constant environmental conditions (continuous resupply of nutrients, constant adjustment of pH, maintenance of a nearly constant cell mass-to-culture volume ratio, etc.) at high cell densities, thereby resulting in the yield of ample cellular material for most biochemical studies during the cell cycle. The new mass-culturing system, when utilized to culture synchronous Chlorella pyrenoidosa, yielded approximately three times as much cellular material as a previous nondilution method, in the same time period and in less than one-tenth the culture volume. Although the newly developed mass-culture method was tested with a unicellular green alga, the basic method should be readily adaptable to synchronous cultures of other microorganisms and to cells in tissue culture.