ABSTRACT
Glycogen is probably one of the oldest types of carbon storage in the living world. In the cytosols of Archaea, Bacteria and Eukaryota, glycogen molecules form tiny hydrosoluble particles, composed of linear chains of glucosyl units joined by α-1,4 glucosidic bonds and hooked together by α-1,6 glucosidic bonds, referred to as branching points. The effectiveness of storing or fueling the cell with a large amount of glucose in a short-term period explains the success of this storage polysaccharide, as well as the independent evolution of glycogen metabolism pathways in the living world. The purpose of this chapter is to update readers with basic knowledge of the storage polysaccharide metabolism in microorganisms, and also to highlight the importance of structure-function relationship, that determines the physicochemical properties of storage polysaccharides.
