Application of a statistical design to the optimization of culture medium for α-amylase production by Aspergillus niger ATCC 16404 grown on orange waste powder Original Research Article

The production optimization of α-amylase (E.C.3.2.1.1.) from Aspergillus niger ATCC 16404 fungus is obtained with statistical experimental designs. The methodology was based on the Plackett–Burman design (N = 12) [12 experiments and 11 factors in which seven are real ones (agitation, pH, starch, yeast extract, “corn steep liquor”, CaCl2, and salts: MgCl2, 6H2O, MnSO4 and FeSO4, 7H2O) and four errors]. This design has been chosen in order to select the factors favoring enzyme production. The production medium is prepared using orange waste powder (2% w/v) at 30 °C under agitation. The statistical analysis has revealed that variation in agitation from 150 rpm to 200 rpm has no effect on the production of α-amylase and that of protein; whereas such as a variation increases the biomass. As for the variation in the pH from 5 to 6 has a positive effect on the production of both α-amylase and proteins, while its effect on the biomass is negative. The addition of starch at 10 g/l to the fermentation medium (an inductive substrate and a carbon source) stimulated the production of α-amylase, while it is without any effect on the production of other protein and that of the biomass.