Cellulase is any of several
enzymes produced chiefly by
fungi,
bacteria, and
protozoans that
catalyze cellulolysis, the decomposition of
cellulose and of some related
polysaccharides; specifically, the
hydrolysis of the 1,4-beta-D-
glycosidic linkages in cellulose,
hemicellulose,
lichenin, and cereal
beta-D-glucans. Cellulases break down the cellulose molecule into
monosaccharides ("simple sugars") such as beta-
glucose, or shorter polysaccharides and
oligosaccharides. The name is also used for any naturally occurring mixture or complex of various such enzymes, that act serially or synergistically to decompose cellulosic material.