Nephelometric and turbidometric assays of cellulase activity

Extensively ball-milled cellulose fibers were used as natural substrate for the determination of cellulase activity. This physical treatment breaks the large cellulose fibers to small but insoluble particles yielding a substrate accessible for complete enzymatic breakdown. The parameters studied to estimate the activity of cellulases were (a) the decrease in optical density of ball-milled suspension of fibers and (b) simultaneous measurement of liberated sugars during hydrolysis. A good correlation was found between the initial rate of reaction and the amount of sugar released at given times.