Methods for measuring cellulase activities

The physical heterogeneity of the substrate and the complexity of the cellulase enzyme system present those wishing to measure cellulase activities with formidable problems. Faced with the use of substrates that are ill defined, and an enzyme system that consists often of a multitude of enzymes acting in synergism in a manner not yet fully understood, the enzymologist has developed a bewildering number of assays in an attempt to throw some light on the complex enzymatic interactions involved in the breakdown of cellulose. This state of affairs, compounded by the existence of a plethora of arbitrary units of activity, has made comparison of quantitative data obtained in various laboratories impossible. This chapter describes a number of alternative assay methods that may help toward a better evaluation of cellulase components and their complex interactions that result in the solubilization of cellulose. Some of these alternative methods are included for practical considerations and many are included because of the nature of the unresolved problems.