The Effect of D-Glucose and D-Fructose on the Activity of β-Glucosidase in Trichoderma Reesei C30 Cellulase
One of the obstacles that needs to be overcome before the enzymatic hydrolysis of cellulose to glucose is realized commercially, β-glucosidase component of cellulase by glucose. As a result of this inhibition, cellobiose accumulates which, in turn, inhibits the other cellulase components and effects a drastic reduction in the rate of the enzymatic hydrolysis of cellulose. The effect of exo-genously added D-glucose and D-fructose on the initial rates of cellobiose and ρ-nitrophenyl-β-D-glucoside (PNPG) hydrolysis, catalysed by the β-glucosidase component in T. reesei C30 cellulase, was determined. β-glucose inhibited the activity of this D-glucosidase competitively with Ki values of 0.5mM and 8.7mM when cellobiose or PNPG was used as the substrate respectively. The inhibition appeared to be pH dependent with maximum inhibition at pH 4.8. No inhibition was observed of this 3-glucosidase, even at concentrations as high as 100mM which caused only 23% inhibition of enzyme activity. It is possible that a high rate of enzymatic cellulose hydrolysis could be maintained if glucose, as it is formed, is converted to fructose by a suitable preparation of glucose isomerase.