Research Article

Production of Proteolytic Enzymes by a Keratin-Degrading Aspergillus niger

Table 2

Experimental design and results of the 22 factorial design.

Run 𝑋 1 (concentration, g/L) 𝑋 2 (pH) 𝑌 1 (proteolytic activity U/mL) 𝑌 2 (keratinolytic activity U/mL)

1−1 (10)−1 ( 3 ) 2.250
2−1 (10)+1 (7)0.381.19
3+1 (30)−1 ( 3 ) 3.690.29
4+1 (30)+1 (7)4.321.22
50 (20)0 (5)10.870.54
60 (20)0 (5)10.360.84
70 (20)0 (5)12.030.75
80 (20)0 (5)10.800.68
90 (20)−1.41 (2.20)4.170.52
100 (20)+ 1.41 (7.80)1.121.73
11−1.41 (6)0 (5)3.730.55
12+1.41 (34)0 (5)11.770.20