pH-dependent adsorption of cellulases to protein-extracted lucerne fibres

The capacity of protein-extracted lucerne fibres to bind the cellulases of the mesophilic fungus Trichoderma reesei , and the thermophilic actinomycete Thermomonospora curvata , was determined to evaluate the fibre as a cellulase-recycling vehicle during bioconversion processes. Adsorption of fungal and bacterial cellulase complexes was minimal at the pH optima (5-0 and 6-2 respectively) for fibre conversion to soluble sugars. Lowering of incubation temperature to 3°C enhanced adsorption of fungal cellulases, but had no effect on bacterial cellulase adsorption. However, adsorptive capacity for either could be improved about 30% by raising the pH above the hydrolysis optimum during the recycling phase.