Physical parameter optimization of cellulase production by Aspergillus niger on solid-state fermentation of cassava waste

Abstract

Cellulases are a group of hydrolytic enzymes and are capable of degrading lignocellulosic materials contain carbohydrate polymers such as cellulose, hemicelulose and starch. Cellulases have wide range of applications. In this study, cellulase production was carried out in solid-state fermentation using cassava waste as a substrate by using Aspergillus niger. Different fermentation conditions were examined to assess their effect in optimizing enzyme production. The effects of various process variables were studied for optimum production of cellulase enzyme using cassava waste including moisture content (%), fermentation time (day) and inoculums size (ml). Fermentation of A.niger with cassava waste substrate will produce cellulases. Cellulases enzyme will degrade cellulose to the smaller glucose units. The production of cellulase was determined based on glucose concentration. Full factorial composite experimental design and central composite design (CCD) were used in the design of experiments and analysis of results. The result indicated that the optimal condition for fermentation of 5 g cassava waste substrate by A.niger was obtained at 100 % of moisture content, 7.95 days of fermentation and 3.78 ml of inoculums size. The coefficient of determination obtained was 0.9125 shows the model adequacy was very satisfactory.