Cellulose is degraded by numerous species of both bacteria and fungi. These organisms
rely on extracellular enzymes that either are secreted into their immediate surroundings
or are located on the cell surface. It is necessary that cellulose be
degraded outside the microbial cell (Fig. 3.1), and that the insoluble macromolecule
s be degraded to monomer s, or oligomer s of a few glucose units (Fig. 3.1), such
as cellobiose , which can be taken into the cell and metabolized