A simplified method for the isolation and estimation of cell wall bound glycogen in Saccharomyces cerevisiae

Abstract

Glycogen is an important storage reserve in yeast. In Saccharomyces cerevisiae glycogen is present in two pools, an intracellular soluble pool and a cell wall bound, insoluble extra-cellular pool. The present method uses a 20% KOH treatment to separate the two pools, which are then estimated using amyloglucosidase. The amount of soluble glycogen was found to be 6.5 mg/g of wet weight of yeast while that of cell wall bound glycogen was found to be almost three times that of the soluble, viz., 18 mg/g of wet weight of yeast. The data is compared with two earlier commonly used methods of yeast carbohydrate fractionation, which reported glycogen in totality. Reviewing these methods in the light of finding two pools of glycogen revealed that both the methods can be demonstrated to yield soluble glycogen in the range of 6-9 mg/g of yeast and 18-21 mg/g of wet weight of yeast of cell wall bound glycogen. © 2008 The Institute of Brewing & Distilling.