Economic Mass Cultivation of Paramecium tetraurelia on a 200‐Liter Scale¹

A new and inexpensive medium is described for axenic mass cultivation of Paramecium tetraurelia stock 51s and the double mutant pawn A/pawn B. Skim milk powder is the major carbon and nitrogen source in this medium. Growth characteristics (proliferation rate, final cell density, and cell size) are similar to those observed with other axenic culture media. Cultures were run in one‐liter erlenmeyer flasks, a 20‐liter, and a 250‐liter airlift bioreactor. The yield of a large bioreactor is 750 g (wet wt.) Paramecium or 5 × 10 9 cells. This easy, economical culture technique will greatly facilitate the use of Paramecium as a model organism for extensive biochemical studies.