EFFECT OF ZINC AND COBALT ON YEAST GROWTH AND FERMENTATION

Yeast grown at 30° C. in a synthetic medium containing protein yields a greater crop when zinc at 50 μg./ml. is added, but the yeast is more prone to autolysis. In a medium lacking protein, there is a similar stimulatory effect but the zinc has little effect on autolysis. If the yeast is grown at 35° C. in the synthetic medium containing protein, the addition of zinc at 50 μg./ml. has little effect. In similar experiments at 30° C. with cobalt in the range 5–50 μg./ml., protein utilization by the yeast is stimulated but growth is retarded.