Utilization of water hyacinth cellulose for production of cellobiase-rich preparation by Aspergillus niger 1.

Production of a cellobiase-rich preparation by Aspergillus niger 1 was achieved using water hyacinth cellulose as the sole carbon source in the culture medium. Production of cellobiase, carboxymethylcellulase (CMC-ase) and filter paper (FP)-cellulase was favoured by controlling the pH of the culture medium during fermentation at 5.0. Sodium citrate (0.5%), sodium phytate (0.1%), Tween-80 (0.2%, v/v) and asparagine (0.07%) had stimulating effects on the productivity of cellobiase, CMC-ase and FP-cellulase. Potassium dihydrogen phosphate doubled the yield of CMC-ase but had a slight effect on FP-cellulase and cellobiase. Wheat bran had a pronounced stimulating effect on the production of cellobiase and CMC-ase. The combined effects of these stimulators resulted in an enzyme preparation rich in cellobiase and contained 18.5, 0.29 and 2.21 U/ml of cellobiase, FP-cellulase and CMC-ase, respectively. A high cellobiase/FP-cellulase ratio of 63.8:1 was thus obtained with the fungal enzyme preparation. The cellobiase activity was maximal at pH 5.0 and showed good thermostability.