Utilization of agricultural wastes for production of useful metabolites requires hydrolysis using both cellulase and amylase enzymes. We isolated Aspergillus fumigatus IB-A1 and evaluated its ability to simultaneously produce both cellulase and amylase. Although the isolate could produce both cellulase and amylase from either soluble starch or carboxymethyl cellulose, amylase activity was higher with soluble starch while cellulase activity was higher when carboxymethyl cellulose was used as the sole carbon source. With a mixture of carboxymethyl cellulose and soluble starch, both the amylase and cellulase activities increased with increase in the ratio of soluble starch. The optima ratio of carboxymethyl cellulose to soluble starch for cellulase and amylase activities were 0.7:0.3, and 0.4 to 0.6 respectively. For practical application, the optimum ratio of carboxymethyl cellulose to soluble starch in the production medium depends on the relative composition of cellulose and starch in the substrate to be hydrolyzed. The isolate was also able to efficiently produce both amylase and cellulase from cassava peel. With 10 g/L cassava peel, the cellulase and amylase activities were 6.122± 0.320 U/ml/min and 4.342± 0.210 U/ml/min respectively. When the cells were immobilized on loofa sponge and subjected to alternating air phase- liquid phase culture, cellulase and amylase production from cassava peel increased to 8.106± 0.620 U/ml/min and 5.206± 1.24 U/ml/min respectively. The optimum ratio of the air phase to the liquid phase was 3 hours of air phase to 21 hours of liquid phase.
Ezea Ifeanyi Boniface, Murata Yoshinori and Ogbonna James Chukwuma
