
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.
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