An Optimization Study of α-Amylase Production by <i>Aspergillus niger</i> ATCC 16404 Grown on Orange Waste Powder

Abstract

In this work, sequential optimization strategy, based on statistical designs, was employed to enhance the production of α-amylase by Aspergillus niger ATCC 16404. This statistical study consists of optimizing the factors that influence the production of α-amylase of A. niger ATCC 16404. Indeed, another statistical study has allowed the selection of 5 factors (pH, starch, yeast extract, “corn steep liquor”, CaCl 2 and salts) affecting both the development of mould (biomass) and that of the enzyme production. The central composite design allows the determination of the optimum of these selected factors and a quadratic model explains the factor reaction. Thus, the “ridge analysis” method, has led to maximizing the experimental reaction. The results indicate that the production rate of α-amylase is maximized in the presence of starch at 8.97 g/l, yeast extract at 2.86 g/l, CaCl 2 at 1.224 g/l, salts (composed of 25% FeSO 4 , 7H 2 O, 25% MnSO 4 and 50% MgCl 2 , 6H 2 O): FeSO 4 , 7H 2 O, MnSO 4 0.1518 g/l and MgCl 2 , 6H 2 O at 0.3036 g/l. As for the pH, it is maintained at the rate of 5.68.