A given number of drops (10) of a yeast suspension in KCl 150 mol m_3 was grown in 25 cm3 of synthetic medium (kg m_3): glucose, 20; peptone, 10; and yeast extract, 10; in a 250 cm3 bottle on a rotating shaker (New brunswick, INNOVA40, NJ, USA) at 20 rad s_1, 28 _C for 18 h.