Cellulase refers to a family of enzymes which act in concert to hydrolyze cellulose. Cellulases are widely distributed throughout the biosphere and are most manifest in fungal and microbial organisms.

At least two steps in cellulose degradation by microorganisms begin with the preparatory prehydrolytic. The first step involves an enzyme (C1) which swells and/or hydrates anhydroglucose chains. The second step uses hydrolytic enzymes (Cx) and beta glucosidase (cellobiase).

Trichoderma reesei has an extensively studied cellulase enzyme complex. This complex converts crystalline, amorphous, and chemically derived celluloses quantitatively to glucose. The vital characteristics of this cellulase complex are:

• The system is multienzymatic;

• At least three enzyme components are both physically and chemically distinct; and

• All three components play essential roles in the hydrolysis of cellulose to glucose.

The assay for cellulase activity uses a method which determines the effect of cellulase on microcrystalline cellulose with respect to glucose formation. Released glucose is determined in a hexokinase/glucose-6-phosphate dehydrogenase system at 340 nm.