ABSTRACT

Cellulases are a group of hydrolytic enzymes, capable of degrading lignocellulosic materials.and have wide range of applications. The aim of this study was to produce cellulase by Aspergillus niger via submerged fermentation of saw dust. Sawdust samples were collected and subjected to heat and acid pretreatment heat while the control was unpreated. The flasks containing pretreated sawdust were inoculated A. niger using and fermentation was carried out for 10 d. Parameters analyzed were; pH, reducing sugar, fungi biomass and cellulase concentration at every 2 d intervals. Subsequently optimization of the process was studied using various nitrogen sources (Ammonium Nitrate, Ammonium chloride, Ammonium sulphate and Urea). The result showed that acid preteatreated Sawdust medium had the highest fungal biomass and cellulase activity of 0.39 ± 0.14 g/l and 1.91 ± 0.30 g/l after 6 d while the lowest 0.33 ± 0.08g/l and 0.003 ± 0.00 g/l for control medium respectively. For the various nitrogen sources result, the highest fungal biomass and cellulase activity of 0.51 ± 0.15g/l and 5.13 ± 0.30 g/l  respectively were from medium supplemented with   ammonium nitrate. The need to augment existing cellulase production processes, cannot be overemphasized, this research has shown that Aspergillus niger can successfully be exploited for appreciable production of cellulase using sawdust as substrate.