Yeast, as all other organism, has to make preparations for survive hard times. For this purpose yeast synthesizes glucose to glycogen and trehalose. The energetic state of the yeast cell to produce the storage carbohydrates, glycogen and trehalose, is of importance to understand the optimization of metabolism under cellular “stress” conditions, as might be found at the end of fermentation. Glycogenesis and glycogenolysis have consequences on brewing yeast cell populations and subsequent fermentation efficiency.[1]

Reverse carbohydra in yeast metabolism