In this paper a comparative study of saccharification of cellulose-rich switchgrass biomass by various enzyme preparations (Accelerase 1500, GC 220, NZ50013 and CTec 2) has been carried out. Furthermore, an effect of supplementary â- glucosidase on activity of enzymes and yield of sugars has been studied. It was found that adding of â- glucosidase to enzyme preparations improves cellulolytic activity and increases the yield of glucose after enzymatic hydrolysis of the cellulosic biomass. In order to evaluate the yield of glucose (Y) from cellulosic substrate after its cleavage by different enzymatic preparations, a combined parameter of cellulolytic activity, P=L2/D, has been profull posed;whereLis used level of cellulolytic activityexpressed in FPU per 1g substrate; and D is used doze of the enzyme expressed in mg proteins per 1g substrate. There is a directlyproportional dependence between yield of glucose and combined parameter of cellulolytic activity.Due to high squared correlation coefficient (R2 = 0.934), the regression equationY= k P can be used to predict the yield of glucose from the biomass hydrolyzed bydifferent enzyme preparations.